What is the meaning of DO IT-JACK. Phrases containing DO IT-JACK
See meanings and uses of DO IT-JACK!DO IT-JACK
2017 film
Jack Do? is a 2017 American short surrealist crime drama mystery film written, directed, and edited by David Lynch. Presented in black-and-white, it follows
What_Did_Jack_Do?
Physical jumping exercise
people were measured doing jumping jacks (for one minute) in 24 hours. "The Jumping Jack Is Named after Its Inventor, General 'Black Jack' Pershing". Vandiver
Jumping_jack
Figure of speech
Look up jack of all trades in Wiktionary, the free dictionary. "Jack of all trades, master of none" is a figure of speech used in reference to a person
Jack_of_all_trades
1972 single by Steely Dan
"Do It Again" is a 1972 song composed and performed by American rock band Steely Dan, who released it as a single from their debut studio album Can't Buy
Do_It_Again_(Steely_Dan_song)
American actor and filmmaker (born 1937)
luck of having Jack Nicholson there. He knows what he's doing, and he comes to play, every time out, full-out performance! And what it says to a lot of
Jack_Nicholson
American musician (born 1984)
Jack Michael Antonoff (born March 31, 1984) is an American singer, songwriter, multi-instrumentalist, and music producer. He is the lead vocalist of the
Jack_Antonoff
2025 mixtape / EP by Stray Kids
instincts, and move forward" by "just do[ing] it". Self-dubbed as a "New Pop", "Divine" includes the '90's funky new jack swing and boom bap-based old-school
Do_It_(mixtape)
Flag of the United Kingdom
.. This is the only occasion when it correct to describe the flag as the Union Jack". However, this assertion does not appear in any Reed's Nautical Almanac
Union_Jack
1967 studio album by Jack McDuff
Do It Now! is a 1967 album by the organist Brother Jack McDuff which was his third release on the Atlantic label. Scott Yanow in his review for AllMusic
Do It Now! (Jack McDuff album)
Do_It_Now!_(Jack_McDuff_album)
Brazilian rock/blues band
O Bando do Velho Jack (in English: "Old Jack's Gang" or "Old Jack's Band"), or simply "O Bando", is a Brazilian rock/blues band formed in 1995 in the
O_Bando_do_Velho_Jack
Topics referred to by the same term
comic variant is to let "Jack" - the supposed brother of George - do it instead. Let George Do It can also refer to: Let George Do It (radio), American radio
Let_George_do_it
Topics referred to by the same term
It Now! (Jack McDuff album), 1967 Let's Do It Now, a 1999 album by Haddaway "Do It Now (Mashd N Kutcher song)", a 2014 song by Mashd N Kutcher "Do It
Do_It_Now
English pirate (died 1720)
any other name for Rackham. It is not until 1728, with the release of the second volume of A General History does "Calico Jack" appear in writing. This nickname
John_Rackham
Unidentified serial killer in London in 1888
Jack the Ripper was an unidentified serial killer active in and around the impoverished Whitechapel district of London, England, in 1888. In both criminal
Jack_the_Ripper
2007 studio album by O Bando do Velho Jack
Bicho do Mato is the fifth album from Brazilian blues/rock band O Bando do Velho Jack, and was released in 2007. "O Bando do Velho Jack". Band Camp. Retrieved
Bicho_do_Mato
22nd episode of the 4th season of 30 Rock
Liz Lemon (Tina Fey), who is scheduled to do a reading at the ceremony, wastes time so that her boss, Jack Donaghy (Alec Baldwin), after sending her a
I_Do_Do
2015 concert tour by Charli XCX and Bleachers
The Charli and Jack Do America Tour (also known as The America Tour) was a co-headlining tour by British singer Charli XCX and American rock band Bleachers
Charli and Jack Do America Tour
Charli_and_Jack_Do_America_Tour
1993 film directed by John McTiernan
Expendables 2). As Jack and Danny enter the movie theater to find Arnold Schwarzenegger, MC Hammer asks Slater about a deal to do the Jack Slater V soundtrack
Last_Action_Hero
Season of television series
television version of The Jack Benny Program. This was the first season where the show ran every week. The Jack Benny Program at IMDb The Jack Benny Program at
The Jack Benny Program season 11
The_Jack_Benny_Program_season_11
Fictional character and social media account
Jack Kimble, also known by his Twitter username @RepJackKimble, is a fictional and satirical character active on the social media websites Twitter and
Jack_Kimble
Series of novels and stories by Lee Child
Jack Reacher is a series of novels, novellas and short stories by British author Jim Grant under the pen name Lee Child. As of November 2025, the series
Jack_Reacher_(novel_series)
Mechanical, hydraulic, or pneumatic, lifting device
top of the jack is a cast-iron circular pad upon which the jacking post rests. The pad moves independently of the house jack so that it does not turn as
Jack_(device)
Type of dance
with the music, extends the left leg and raises both arms, as if doing jumping jacks; then extends the right leg and raises both arms again. The moves
Freddie_(dance)
American animated television series
nighttime programming block Adult Swim. It was produced by Cartoon Network Studios. Tartakovsky conceived Samurai Jack after finishing his work on his first
Samurai_Jack
American television series (2018–2023)
modern-day interpretations of the original characters, it stars John Krasinski as CIA analyst Jack Ryan. The series was created by Carlton Cuse and Graham
Jack_Ryan_(TV_series)
British producer, agent and TV personality (born 1940)
Backchat with Jack Whithall and His Dad". BBC Three. "Who Do You Think You Are? – Series 16: 3. Jack and Michael Whitehall". BBC. "Jack and Michael Whitehall
Michael_Whitehall
American musician (born 1975)
News. Retrieved January 24, 2006. Handyside 2004, p. 14. "Jack White on Cass Tech: 'It does hurt to see your high school boarded up like that'". July
Jack_White
2012 film by Christopher McQuarrie
21, 2012, where it received generally positive reviews and was successful at the box office. Cruise later starred in a sequel: Jack Reacher: Never Go
Jack_Reacher_(film)
Name used in two figures of speech
"(A)round Jack Robinson's barn" has the opposite connotation, implying slowness, as it is often used to refer to circumlocution, circumvention, or doing things
Jack_Robinson_(idiom)
2005 Singaporean film
I Do, I Do (Chinese: 爱都爱都), is a 2005 Singaporean Chinese New Year romantic comedy film directed by Jack Neo and Lim Boon Hwee. It was the first time Neo
I_Do,_I_Do_(film)
American singer and actor (born 1967)
the new jack swing era with a series of R&B chart hits, including “Talk to Myself” (1989), “I'm Dreamin'” (1991), and “Every Little Thing U Do” (1993)
Christopher_Williams_(singer)
Irish actor (born 1992)
Jack Gleeson (born 20 May 1992) is an Irish actor. He is best known for portraying Joffrey Baratheon in the HBO television series Game of Thrones (2011–2014)
Jack_Gleeson
English comedian, actor, presenter and writer (born 1988)
Jack Peter Benedict Whitehall (born 7 July 1988) is an English comedian, actor, writer and television personality. He is known for his roles as JP in the
Jack_Whitehall
American actor, comedian, singer, and musician (born 1969)
highest heights, it's almost like a spiritual feeling. It fills that void for me. "Jack Black Will Do Anything To Get Into Hebrew School". Conan. TBS. April
Jack_Black
English footballer (born 1995)
Jack Peter Grealish (born 10 September 1995) is an English professional footballer who plays as a left winger or attacking midfielder for Premier League
Jack_Grealish
American actor (1920–2003)
William Scott "Jack" Elam (November 13, 1920 – October 20, 2003) was an American film and television actor best known for his numerous roles as villains
Jack_Elam
2017 single by Taylor Swift
public image in 2016. Written and produced by Swift and Jack Antonoff, "Look What You Made Me Do" has an electronic production combining electropop, dance-pop
Look_What_You_Made_Me_Do
Fictional character from Will and Grace
John Philip "Jack" McFarland is a fictional character on the American television sitcom Will & Grace, played by Sean Hayes. Jack is Will Truman's (Eric
Jack_McFarland
Season of television series
The fifth and final season of Samurai Jack, an American animated series, premiered on Adult Swim's Toonami programming block on March 11, 2017, and concluded
Samurai_Jack_season_5
Season of television series
two. It takes place primarily in Los Angeles but also in northern Mexico when Jack Bauer meets a family of drug dealers. Throughout the day, Jack Bauer
24_season_3
American series of action films depicting the character created by Tom Clancy
The Jack Ryan franchise consists of American action-thriller installments, based on the fictional titular character from a series of novels written by
Jack_Ryan_(franchise)
Character from the television series 24
Jack Bauer does and gradually becomes more rogue and puts justice before the job. When first meeting Jack, Renee is reluctant to do things that Jack Bauer
Renee_Walker
American nightclub owner and murderer of Lee Harvey Oswald (1911–1967)
Jack Leon Ruby (born Jacob Rubenstein; c. March 25, 1911 – January 3, 1967) was an American nightclub owner. He murdered Lee Harvey Oswald two days after
Jack_Ruby
pregnant with his child, but he does not fall for either of her ruses. It is then Angelica finally admits her love for Jack, who is somewhat touched by this;
List of Pirates of the Caribbean characters
List_of_Pirates_of_the_Caribbean_characters
Kind of cheese
eaten by itself, it is frequently marbled with Colby to produce Colby-Jack, or with yellow cheddar to produce cheddar-Jack. Pepper Jack is a version flavored
Monterey_Jack
Fictional character on 30 Rock
way he [Jack] looks at you that he's serious". Colleen Donaghy, Jack's mother, thinks that Liz is a perfect match for Jack. In "Do-Over", Jack and Liz
Liz_Lemon
2000 studio album by Craig David
Born to Do It is the debut studio album by English singer Craig David, released in the United Kingdom on 14 August 2000 by Wildstar Records and in the
Born_to_Do_It
Character in Dawson's Creek
"thing" for Jack. After he makes it perfectly clear that he does not wish to take Toby to the gang's senior prom, Jen goes against Jack's wishes and tells
Jen_Lindley
2024 single by Taylor Swift
Tortured Poets Department (2024). Written and produced by Swift and Jack Antonoff, "I Can Do It with a Broken Heart" depicts Swift's concealment of depression
I Can Do It with a Broken Heart
I_Can_Do_It_with_a_Broken_Heart
American variety of cheese
Colby-Jack, or Co-jack/Cojack, is an American marble cheese made from Colby and Monterey Jack. It is classified as semi-hard in texture and is mild due
Colby-Jack
American comic book artist (1917–1994)
recalled in 1988, "I loved Jack's work and the first time I saw it I couldn't believe what I was seeing. He asked if we could do some freelance work together
Jack_Kirby
American fast-food restaurant chain
Jack in the Box, Inc. is an American fast food restaurant chain founded on February 21, 1951, by Robert O. Peterson in San Diego, California, where it
Jack_in_the_Box
Chinese business magnate and investor (born 1964)
10 September 1964), also known as Jack Ma, is a Chinese businessman and philanthropist. He is the founder of the Jack Ma Foundation, and co-founder of
Jack_Ma
Television pilot featuring Jack Black and Owen Wilson
it has the time to do it because Jack's doing a movie like every other month, and he has a kid now. Heat Vision and Jack at IMDb Heat Vision and Jack
Heat_Vision_and_Jack
Season of television series
its trajectory and intercept it. As Jack closes in on Marwan and the missile's location, Chinese agents find proof that Jack Bauer invaded their territory
24_season_4
Video game series
series began with You Don't Know Jack (1995), and combines trivia and comedy within a game show framing device. While it is primarily a PC and Mac-based
You Don't Know Jack (franchise)
You_Don't_Know_Jack_(franchise)
American actor, singer and director (1927–1976)
and Mairin Cassidy by son Shaun; Cole and Jack by son Patrick; and, Meghan Mae by son Ryan. His grandson, Jack Cassidy, was a contestant on the singing
Jack_Cassidy
1998 film by Mike Hodges
killed in an apparent hit-and-run. Jack finishes his book and gets it published anonymously. It is a big success, but he does not change anything about his
Croupier_(film)
Protagonist of the Pirates of the Caribbean film series
makes off, Lieutenant Groves asks: "Do you think he plans it all out, or just makes it up as he goes along?" Jack also tricks Blackbeard into saving his
Jack_Sparrow
American pop-rap duo
Jack & Jack are an American pop-rap duo from Omaha, Nebraska, consisting of Jack Johnson and Jack Gilinsky, based in Los Angeles, California. After success
Jack_&_Jack
British tennis player (born 2001)
Jack Alexander Draper (born 22 December 2001) is a British professional tennis player. He has a career-high ATP singles ranking of world No. 4, achieved
Jack_Draper
1927 film by Alan Crosland
as Mama does." Two weeks after Jack's expulsion from the family home and 24 hours before the opening night of April Follies on Broadway, Jack's father
The_Jazz_Singer
Album by Jack Bruce
Always Wanted to Do This is the seventh studio album by Scottish musician Jack Bruce, released in December 1980 and credited to "Jack Bruce and Friends:
I've_Always_Wanted_to_Do_This
English fairy tale
"Jack and the Beanstalk" is an English fairy tale with ancient origins. It appeared as "The Story of Jack Spriggins and the Enchanted Bean" in 1734 and
Jack_and_the_Beanstalk
American film by Mike Flanagan
Dan does [is] Jack's story from [the original novel]" and that he "really wanted to try to bring back the ending from The Shining novel and give it to
Doctor_Sleep_(2019_film)
1995 single by Montell Jordan
"This Is How We Do It" is the debut single of American singer-songwriter Montell Jordan. It was released by Def Jam Recordings in February 1995, as the
This_Is_How_We_Do_It
American rapper (born 1991)
2017. Retrieved October 24, 2017. ".@zanelowe: "Does it have a title?" @QuavoStuntin: "Huncho Jack, Jack Huncho" Quavo says his project @trvisXX is being
Travis_Scott
Fictional character from EastEnders
business or his family, he will do whatever he needs to do to eliminate that problem." In April 2011, it was reported that Jack would have a one-night stand
Jack_Branning
American lawyer (born 1969)
well as to fire Jack Smith's entire team. In January 2025, Jack Smith provided the report to the attorney general (as he is required to do by law) and resigned
Jack_Smith_(lawyer)
American actor (1907-1981)
Harold "Jack" Albertson (June 16, 1907 – November 25, 1981) was an American actor, comedian, dancer and singer who also performed in vaudeville. Albertson
Jack_Albertson
American singer-songwriter (born 1975)
Jack Hody Johnson (born May 18, 1975) is an American singer-songwriter. He plays a variety of styles including pop, rock, acoustic, folk, and surf rock
Jack_Johnson_(musician)
1996 film by Francis Ford Coppola
Jack has the body of a 40-year-old man. One day, four boys are lurking outside of his house, intrigued by rumors of a monster inhabiting it. Jack scares
Jack_(1996_film)
British-Italian singer and musician
Nero Paul Ettinger (who had previously seen Jack perform at Tony Moore's venue in Hammersmith) that Jack do a tour of the cafés, becoming the first label
Jack_Savoretti
1971 film directed by Tom Laughlin
Billy Jack is a 1971 American action drama independent film, the second of four films centering on a character of the same name (played by Tom Laughlin
Billy_Jack
American actor and comedian (born 1973)
Jack McBrayer (/məkˈbreɪ.ər/; born May 27, 1973) is an American actor and comedian. He gained national exposure for his portrayal of Kenneth Parcell in
Jack_McBrayer
Fictional character by Lee Child
Jack Reacher is the protagonist of a series of crime thriller novels by British author Lee Child, a 2012 film adaptation, its 2016 sequel, and a television
Jack_Reacher
que une Vinny e LS Jack | Diário do Pará". Diário do Pará (in Brazilian Portuguese). 2020-02-18. Retrieved 2020-02-19. "Vinny, do hit 'Heloísa, mexe a
LS_Jack
Fictional title character of Samurai Jack
father's sword. In Episode XCVIII, Jack and Ashi return to the mountain where Jack lost his sword, but do not find it, and Jack concludes that, after spilling
Samurai_Jack_(character)
American fitness and nutrition guru and motivational speaker (1914–2011)
to do a jumping jack.[citation needed] 1956 (age 42) – Set what was claimed as a world record of 1,033 push-ups in 23 minutes on You Asked For It, a television
Jack_LaLanne
American actor (born 1987)
Sena (/dəˈsɛnə/; born December 6, 1987), better known by his stage name Jack DeSena, is an American actor and comedian. He is best known for his work
Jack_DeSena
1974 novel by John Christopher
could hold ten times as much people as they do, they tell him he ought to go into the Outlands and join "Wild Jack," the infamous "bogeyman who would creep
Wild_Jack
2005 American comedy film
When Do We Eat? is a 2005 American comedy film directed by Salvador Litvak and starring Michael Lerner, Lesley Ann Warren, Jack Klugman, Shiri Appleby
When_Do_We_Eat?_(2005_film)
English nursery rhyme
"Little Jack Horner" is a popular English nursery rhyme with the Roud Folk Song Index number 13027. First mentioned in the 18th century, it was early
Little_Jack_Horner
2021 British comedy film by Jack Clough
People Just Do Nothing: Big in Japan is a 2021 British mockumentary comedy film directed by Jack Clough, serving as a continuation of the television series
People Just Do Nothing: Big in Japan
People_Just_Do_Nothing:_Big_in_Japan
American boxer (1895–1983)
anything to do with the taping of Jack's hands was Deforest.[clarification needed] Kearns had nothing to do with it, so his plaster of Paris story is
Jack_Dempsey
English actor (born 1990)
Jack O'Connell (born 1 August 1990) is an English actor. Known for his roles as dark, volatile and menacing characters, he has received various accolades
Jack_O'Connell_(actor)
English nursery rhyme
"Jack and Jill" (sometimes "Jack and Gill", particularly in earlier versions) is a traditional English nursery rhyme. The Roud Folk Song Index classifies
Jack_and_Jill
2008 film by Tom Vaughan
getting married. The next morning, agreeing it was a mistake, they plan to divorce. Before they can do so, Jack uses a quarter Joy gives him in a slot machine
What_Happens_in_Vegas
1991 film by Wolfgang Petersen
provided as a private investigator to follow Judith, and it revealed she was cheating with Jack Stanton. Judith arranges a meeting with Stanton and Dan
Shattered_(1991_film)
2007 film by Gregory M. Wilson
Gregory M. Wilson and written by Daniel Farrands and Philip Nutman. It is based on Jack Ketchum's 1989 novel of the same name, which was inspired by the
The Girl Next Door (2007 film)
The_Girl_Next_Door_(2007_film)
2002 film by Phil Alden Robinson
the same name. The film, which is set in the Jack Ryan franchise, is a reboot taking place in 2002. Jack Ryan is portrayed as a younger character by Ben
The_Sum_of_All_Fears_(film)
Family of connectors typically used for analog signals
mandating physical sockets, do provide specifications for a front panel connector with pin assignments for two ports with jack detection. Front panels commonly
Phone_connector_(audio)
2013 fantasy adventure film by Bryan Singer
Jack the Giant Slayer (previously titled Jack the Giant Killer) is a 2013 American fantasy adventure film directed by Bryan Singer and written by Darren
Jack_the_Giant_Slayer
Italian footballer (born 2005)
Copa do Brasil Sub-17s, two Campeonato Brasileiro Sub-17s, and one Campeonato Paulista Sub-17 between 2022 and 2023. On 2 February 2024, Fellipe Jack moved
Fellipe_Jack
Canadian ice hockey player (born 2000)
McBain's rights". TSN. March 17, 2022. Retrieved April 22, 2022. "What to do about Jack McBain". SB Nation. March 16, 2022. Archived from the original on December
Jack_McBain
Ball sport
the opportunity to bowl. From then on, the side which does not have the ball closest to the jack has a chance to bowl, up until one side or the other has
Bocce
American actor and screenwriter
Jack Coleman. Jack Coleman at IMDb Jack Coleman at the Internet Broadway Database Jack Coleman at the Internet Off-Broadway Database (archived) Jack Coleman
Jack_Coleman_(actor)
1940 British film
Let George Do It! (also known as Murder in Bergen; US title: To Hell With Hitler[citation needed]) is a 1940 British black-and-white comedy musical war
Let_George_Do_It!
Fusion genre of music
termed new jack swing. It sparked a revolution." Riley stated that before new jack swing, "rappers and singers didn't want anything to do with one another"
New_jack_swing
English actor (born 1973)
Jack Arthur Davenport (born 1 March 1973) is an English actor. He is best known for his roles in the television series This Life and Coupling, and as James
Jack_Davenport
Slangs & AI meanings
If you drive along a motorway in the wrong lane the police will do you. You could then tell your friends that you have been done by the police. Prosecute is another word for it!
Elementary school euphemism for "sex" or "have sex". As a seven-year-old, the contributor knew that if he ever used the word "it" in its original meaning, He'd be mercilessly teased.
n party – you might have a drinks do to celebrate a new job: Pat and Jim are having a do to celebrate their fiftieth anniversary. stag do Bachelor Party.
Whenever the chant "Do! Do! Do! Do!" was heard on the playground you knew there was a fight going on, usually surrounded by a frenzied crowd of children. You could also 'offer someone out' or in other words invite them to a fight by saying "you wanna do?"
To do the sex act; fuck.
Forget it or don’t do it
Taken from the Hall & Oates 80s song 'I Can't Go For That (No Can Do)' meaning, "I can't do it" or "it can't be done."
How do is Dorset slang for how do you do.
do you liek it..do you understand..do you agree
Do the do is Black American slang for to have sexual intercourse.
Do is slang for a cheat or swindle. Do is slang for a robbery.Do is slang for excrement.Do is British slang for assault.
Cannot do it. "You can't come it over me so."
Exclam. Hello! How do you do! [Northern use]
Do you get it?
Go it is slang for to do something or move energetically.
A term used to say, What's up? "Hey kinfolk, what it do?"Â
Do it is slang for to have sex.
If you go into a shop and say "do you do batteries?" it means "do you sell batteries".
DO IT-JACK
Slangs & AI derived meanings
Cool hand Luke is London Cockney rhyming slang for serendipity (fluke).
Rejected
Lethal injection of a narcotic
Crazy person
A pocket handkerchief.
One way or other, by any expedient. "It can't be done by hook or crook.â€
Noun. A male to female preoperative transexual, usually very feminine looking, with breasts and male genitals, a shemale. E.g."Last time I visited Bangkok the streets were lined with chicks with dicks, and they were so gorgeous too."
Homosexual.
Noun. A bigoted narrow minded person. Originally an American term for a ruralised bigot.
DO IT-JACK
DO IT-JACK
DO IT-JACK
DO IT-JACK
DO IT-JACK
pron.
The neuter pronoun of the third person, corresponding to the masculine pronoun he and the feminine she, and having the same plural (they, their or theirs, them).
v. t. / auxiliary
To perform, as an action; to execute; to transact to carry out in action; as, to do a good or a bad act; do our duty; to do what I can.
pron.
As an indefinite nominative for a impersonal verb; as, it snows; it rains.
adv.
Is it thus? do you mean what you say? -- with an upward tone; as, do you say he refuses? So?
n.
A syllable attached to the first tone of the major diatonic scale for the purpose of solmization, or solfeggio. It is the first of the seven syllables used by the Italians as manes of musical tones, and replaced, for the sake of euphony, the syllable Ut, applied to the note C. In England and America the same syllables are used by mane as a scale pattern, while the tones in respect to absolute pitch are named from the first seven letters of the alphabet.
n.
Ado; bustle; stir; to do.
v. i.
To succeed; to avail; to answer the purpose; to serve; as, if no better plan can be found, he will make this do.
pron.
As an indefinite object after some intransitive verbs, or after a substantive used humorously as a verb; as, to foot it (i. e., to walk).
p. p. & a.
Resolved; as, I am bound to do it.
pron.
As a demonstrative, especially at the beginning of a sentence, pointing to that which is about to be stated, named, or mentioned, or referring to that which apparent or well known; as, I saw it was John.
a.
Doing nothing; inactive; idle; lazy; as, a do-nothing policy.
pron.
As a substance for any noun of the neuter gender; as, here is the book, take it home.
v. i.
To fare; to be, as regards health; as, they asked him how he did; how do you do to-day?
v. t. / auxiliary
To see or inspect; to explore; as, to do all the points of interest.
n.
Alt. of Do-nothingness
pron.
As a substitute for such general terms as, the state of affairs, the condition of things, and the like; as, how is it with the sick man?
v. t. / auxiliary
To put or bring into a form, state, or condition, especially in the phrases, to do death, to put to death; to slay; to do away (often do away with), to put away; to remove; to do on, to put on; to don; to do off, to take off, as dress; to doff; to do into, to put into the form of; to translate or transform into, as a text.
interj.
Much good may it do you! -- a familiar salutation or welcome.
n. pl.
Microorganisms which do not require oxygen, but are killed by it.
DO IT-JACK
DO IT-JACK
DO IT-JACK