Gack

Used to describe female pyhsique. Particularly her stomach and breasts. When a female's stomach sticks out further then her breasts. aka (When her gut sticks out further then her rack)

She's got a Gack
When her gut sticks out further then her rack.

by Rob K July 24, 2006

Gack

When you fuck your bitch so hard that her pussy makes a farting sound much like the nickelodeon puddy like material "gack"

Yo dude, last night I gacked the shit out of ashley's pussy.

by ScuryJerry January 16, 2006

gack

The slimy substance (usually green) that was dumped on people in earyl Nickelodeon tv shows

"Thats the incorrect answer so you get drenched by a bucket of gack"

by Cane May 1, 2005

Gack

A really nasty substance. Like ear wax, saliva, boogers etc.

"Dude! Your ear phones are full of gack!"

by PaleteroJ March 27, 2010

GACK!

A word or sound muttered/or written by Professors of Anatomy and Physiology when proper terminlogy is not used. Also used un situations of extreme exacerbation.

Student Answer: Gluteus Med.
Professor Commentary on test: GACK! This is not proper terminology.

"GACK!, be quiet now! Or I will leave!"

by Rojay December 1, 2006

gack

Similar to a circus "geek", a "gack" is a circus performer who sucks farts out of chickens.

It was amazing how the circus gack was able to withdraw flatulence from the hens and roosters.

by J.J.W. November 22, 2004

Gack

A noun used to insult anyone that looks, talks, or acts like a dork.

OMG, don't let Stewart come with us tonight, that dude is a fucking gack.

by Richard Huang November 6, 2004