An Ack is a person with no common sense. An ack is usually a child with slight autism who acts as if they are more solid than the dicks that penetrate them. They also get extremely triggered on any game from Minecraft to Destiny, causing them to have breakdown and cry to their mother. Finally, they seem to have no control over their bowels and often shit themselves, causing every piece of clothing, not just underwear, to be covered in shit stains. In serious cases, an Ack will be unable to agree with anyone else causing everyone, even their own family, to know then as a little bitch.
by Legit Tings December 13, 2016

The one word in the language exposed to the world in Mars Attacks. Can also be used as the sweet sound of music - working particularly well with the Knight Rider theme tune.
by When Dingoes Attack October 3, 2003

by UR MOM GAYYYYYYY March 8, 2018

A word in which one can describe extreme to mild frustration or anger to someone or something. (Mostly used in AIM or other instant messenger conversations).
by Mr. X December 27, 2004

by Bear21 July 14, 2009

A sound that you make to notify a person you are joking. Extra letters can be added to it to show emphasis. Drizzy Drake makes this noise in the song over
ACK!
by Izilluh December 20, 2010

a bad ack, the opposite of a good crack. Can be used to describe something that is particularly substandard or to denote boredom and/or disinterest
"Do you like that new Starsailor Track?" - "Nah it's Ack"
or
"Alright mate how's it going?" - "Not too good pal, the manager at work says that tar..." - "ACK!"
or
"Alright mate how's it going?" - "Not too good pal, the manager at work says that tar..." - "ACK!"
by Huge Ackman September 16, 2003
