Green’s Dictionary of Slang

1. (orig. US) a bad temper.

1965		R. Moore Green Berets 43: Those boys have big case of the ass with us.
1968		B. Hersey letter 16 Mar. at www.ktroop.com 🌐 Oh well, I guess that I’ve got a case of the ‘ass’ because I am short and I want to go home. [...] The sooner that I get out of this damn troop and the 11th Cav the better I will like it.
1982		(con. 1970) J.M. Del Vecchio 13th Valley (1983) 200: You fuckin airhead assholes give me a case of the ass.
1993		P. McGowan Outside the Wire n.p.: The prisoner was a defiant sort that obviously had a case of the ass. Muhammad Qamar possessed a defiant and seething disposition.
2001		in New Yorker 12 Nov. n.p.: These guys have had a case of the ass since Mogadishu. They want to do it right and they train hard. Don’t put them on something stupid.

2. (US campus/gay) something unpleasant, a disappointment.

1989–2003		R.O. Scott Gay Sl. Dict. 🌐 ass: [...] 6. ‘Ass, (The)’: something terrible; a let-down; ex ‘Oh my God, That was the ass!’.
2001		Eble Campus Sl. Fall 1: ASS – bad, unacceptable.