Green’s Dictionary of Slang

a feeble, useless person.

1910		J. London ‘Told in the Drooling Ward’ Complete Short Stories (1993) III 1762: I’m an assistant, expert assistant. That’s going some for a feeb. Feeb? Oh, that’s feeble-minded. I thought you knew. We’re all feebs in here.
1941		F.S. Fitzgerald ‘Mightier than the Sword’ in Pat Hobby Stories (1967) 159: Who’d make up the stories — these feebs?
1952		S.J. Perelman letter 20 June in Crowther Don’t Tread on Me (1987) 130: A plumber and electrician, both of whom are the most exasperating feebs I’ve ever met.
1977		Eble Campus Sl. Apr. 2: feeb – absent-minded person.
1989		(con. 1960) P. Theroux My Secret Hist. (1990) 110: I think he’s a feeb.
1990		(con. c.1970) G. Hasford Phantom Blooper 231: I get up into his face. I say, ‘You shut your mouth, you ridiculous feeb, or I will use your nose as pivot point for an amtrack movement.’.
2005		J. Stahl I, Fatty 178: Roscoe [...] don’t be a feeb.
2015		J. Stahl OG Dad 145: Raising her eyes to mom and dad like we’re a couple of feebs for not being able to undertand her inchoate gurps and burbles.