Green’s Dictionary of Slang

1. (US) a novice, an innocent, a newly arrived immigrant, a fool.

1921		Variety 4 May 9: This giboney comes back with, ‘Sorry, this is a five-story buildin’ and we ain’t got no sixth floor’.
1931		AS VI 439: Jaboney [...] a greenhorn; a newly-arrived foreigner .
1954		Matheson Born of Man and Woman 127: And that jiboney across the hall. He makes life worse than it is [HDAS].
1967		T. Taylor A-18 139: She got the jaboney to marry her, so I didn’t have to support her too long.
1987		S. Jones It All began with Daisy 5: All I do is sit in my nice air-conditioned office and I pick up the phone and I talk to some jaboney for a while and when I hang up I know I’ve made some banker richer.

2. (US) a thug.

1952		(con. 1920s) ‘Harry Grey’ Hoods (1953) 183: I was thinking of [...] having them send me a couple of shabonies, you know, the demolition squad from Mulberry Street, to blow the joint apart.
1952		Esquire June 84: He had a couple of his jiboneys with him.
1976		R. Price Blood Brothers 5: Stony. Chubby. Fuckin’ jibone [...] Jack Palance all right.
1977		E. Torres Q and A 152: You, you fucking jadroney.
1990		R. Campbell Nibbled to Death by Ducks 97: ‘I doubt that,’ the tall jaboney says, and he looks me up and down like he’s ready to step on me and squash me like a bug.
1998		K. Anderson Night Dogs 136: ‘I’m sorry. I guess I’ll just let a bunch of garbones stomp my ass’.
2003		R. Price Samaritan 160: Probably ratting out some Colombian or other to County in order to avoid any kind of serious time. Just like every other jibone out there.

3. (US Und.) an Italian.

1950

Goldin et al. DAUL 110/2: Jibboney. An Italian.