Green’s Dictionary of Slang

(US) nothing, at all; in senses of nothingness, in contexts of giving, getting, speaking, etc.

1966		(con. 1958) R. Farina Been Down So Long (1972) 88: You don’t have a dime, sweetheart [...] and nobody’s going to give you squat, and you know it.
1974		(con. 1960s) R. Price Wanderers 125: Three guineas and two niggers – couldn’t harmonise for squat.
1977		L. Heinemann Close Quarters (1987) 68: I do not give a good squat if you go home tonight!
1983		S. King Christine 361: Then he tightened up and wouldn’t tell me squat.
1998		D. Hecht Skull Session 285: This legal shit doesn’t mean squat to me.
2000		Guardian Space 22 June 22: Dad did absolutely squat.
2001		N. Green Shooting Dr. Jack (2002) 24: If we’da sent Tuco, who we pay squat, he’d have brought cash.
2007		T. Dorsey Hurricane Punch 60: Cops aren’t giving anyone squat, but you got the whole story.
2011		Salon.com 20 Nov. 🌐 No matter how much you think you know about the varied and nuanced spectrum of human sexuality, you realize you don’t know squat until you work in a porn store.
2016		A. Wheatle Crongton Knights 14: ‘Don’t tell Dad zero squat’.
2017		G. Simmons in New Statesman 19 May 🌐 I don’t know why anyone gives a squat what somebody with a guitar round his neck thinks about politics.