Something you don't know.
I don't know jack squats about music
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."
I didn't win jack squat when i went to Las Vegas last weekend.
there are users on this website who do not know jack squat about writing a good definition.
not anything, absolutely nothing
I know jack squat about thermodynamics.
lack of knowledge
You don't know Jack Squat about anything
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.