Green’s Dictionary of Slang

fruity adj.²

(US) crazy; stupid.

1915		‘Doss Chiderdoss’ ‘Comedians All’ Sporting Times 17 Apr. 1/2: Comedians fruity, they grudge us our beer, / And would make us comedians dry.
1915		S. Ford Torchy, Private Sec. 28: ‘I fear Mr. Briscoe thinks unfavorably of it.’ ‘Then he’s fruity in the pan.’.
1953		‘John Eagle’ Hoodlums (2021) 124: Phony as the made-up broads in the movies. They’re for fruity people to worship, then go home to dream.
1966		M. Rumaker Exit 3 and Other Stories 159: That fruity shine’s nuts. Don’t pay attention to him.
1971		R.D. Pharr S.R.O. (1998) 248: ‘You’re going to say I’m fruity as hell for bringing jailhouse love in the street with me’.
1981		Eble Campus Sl. Mar. 3: fruity – having little common sense; spacey.
1990		J. Wambaugh Golden Orange (1991) 185: He’s fruity over cassette players, this Audio Killer.
2000		Indep. Rev. 18 Oct. 1: While some condemned Atlantis as completely fruity, others actually joined the commune.

In phrases

go fruit (v.)

(US) to become obsessed with [but note fruity adj.¹ (2)].

1968

W.R. Burnett Cool Man 69: ‘I told her my wife was driving me crazy because she’d gone fruit for some redheaded guy’.