Green’s Dictionary of Slang

1. (orig. US) a tough person, a thug.

1962		R. Crane Born of Battle 98: Ain’t he a real, genuine hard-ass [OED].
1971–2		C. Shafer ‘Catheads [...] and Cho-Cho Sticks’ in Abernethy Bounty of Texas (1990) 206: hardass, n. – one who is always in trouble with prison officials.
1979		E. Torres After Hours 34: Would-be hard-ass.
1981		M. Baker Nam (1982) 13: I played some football and baseball like everybody else. I was kind of a hard-ass in school.
1992		A. Duff One Night Out Stealing 134: Even the hard-arses in the Tavi said Sonny was a handsome little critter.
1997		C. Hiaasen Lucky You 149: Bode could be a hardass too, but he was more of a thinker.
2000		Indep. on Sun. Culture 16 Jan. 3: Aaron Eckhart describes Neil’s father as ‘a hard-ass’.
2003		J. Lethem Fortress of Solitude 427: Dose’s bunkmate [...] was a hardass he knew from the neighborhood.
2007		W. Ellis Crooked Little Vein 105: He could be a little odd [...] but nothing like this. Bob was a hardass. [Ibid.] 183: You’re funny when you try to be a hardass.
2011		C.F. Holme ‘Night at the Royale’ in Pulp Ink [ebook] He was sick to death of all the hard-asses in his employ fighting over the Mr Black moniker.
2013		T. Robinson Hard Bounce [ebook] The guy is a hard-ass, but he’s a cop, for chrissakes’.
2017		T. Spicer Good Girl Stripped Bare 237: [He] is variously described as a ‘hard arse’, ‘big swinging dick’ and ‘macho bully’.
2020		C. Hiaasen Squeeze Me 31: Not wishing to be viewed as a hard-ass on the handicapped.

2. (US) an insensitive nature; a ‘thick skin’.

2001

J. Stahl Plainclothes Naked (2002) 15: If you think I’m going to answer another fucking question about anything, you’d better have a hard ass.