Green’s Dictionary of Slang

1. (orig. US, also dumb-butt) a fool.

1958		J. David College Vocab. 7: Dumb-ass – One who acts stupid.
1962		(con. WWII) J. Jones Thin Red Line (1963) 388: I don’t know what these dumbasses would do if they didn’t have me around to take care of them.
1972		D. Jenkins Semi-Tough 4: Nobody can help being what he is, whether it turns out to be black as a cup of coffee at a truck stop, or a white Southern dumb-ass.
1984		D. Jenkins Life Its Ownself (1985) 191: Some dumbass missed a block or dropped a pass.
1990		W.D. Myers Mouse Rap 52: [O]ld dumb-butt Leroy talked about how I was going to mess Bobby up.
1997		J. Birmingham Tasmanian Babes Fiasco (1998) 159: You’re supposed to say ‘check’, dumb arse!
1997		(con. 1970s) G. Pelecanos King Suckerman (1998) 217: Why’s a smart guy like you working for a dumb-ass like Eddie?
2000		Willowall ‘Amanda Gets Zipped’ 🌐 Do you really think I’m gonna save you from this you fucking dumb-ass?!
2004		K. Bruen ‘Fade To . . . Brooklyn’ in Brooklyn Noir 308: I’m no dumbass, I’ve learned a lot of stuff.
2008		G. Pelecanos Way Home (2009) 204: Dumbass had his share of the money in the trunk of the car.
2010		Big Issue (SA) 5-26 Feb. 11/2: Instructions not be be seen using the map in public like a dumbass.
2011		S. Kelman Pigeon English 21: Criminal leads, dumb-arse.
2013		Izikhotane News (S. Afr.) 12 Mar. 🌐 Dumb ass is da one who fails tah provide ur needs.
2013		J. Stahl Happy Mutant Baby Pills 114: Harold also swore he didn’t mind the ‘dumbasses’ and ‘morons’ they yelled after him.
2018		‘Aidan Truhen’ Price You Pay 85: Ooo but Jack no we bombed those fuckers in their caves and they are all gooooone! Are they dumbass? Are they really?
2020		D. Winslow ‘The San Diego Zoo’ in Broken 127: But really, what kind of total dumb-ass would toss a revolver away in a zoo?

2. stupidity.

1972		D. Jenkins Semi-Tough 10: ‘I’m what a lot of you spooks might think of as a red neck with a terminal case of the dumb-ass’.
2012		K. Powers Yellow Birds 193: Sergeant Sterling [...] said, ‘Someone had a big old bowl of dumbass today. Get your shit together’.