look up any word, like cunt:
 
4.
not anything, absolutely nothing
I know jack squat about thermodynamics.
by piewire September 19, 2003
 
1.
Nothing, zero, zilch, nada, shit all. Possibly a short, fat man.
"I came out of that deal with jack squat."
"Here comes that prick, Jack Squat."
by chico del nacho September 19, 2003
 
2.
absolutely nothing
I didn't win jack squat when i went to Las Vegas last weekend.
by Natalie September 20, 2003
 
3.
Another way to say Jack Shit.
there are users on this website who do not know jack squat about writing a good definition.
by Light Joker May 21, 2004
 
5.
lack of knowledge
You don't know Jack Squat about anything
by Hoboken Johnny September 20, 2003
 
6.
Something you don't know.
I don't know jack squats about music
by Mr13BF July 07, 2012
 
7.
Nothing. Identical in meaning to jack shit - it's just an equivalent for people who are scared of profanities.
Your car's worth jack squat.
by super ultra hyper bishi bashi champ September 21, 2003