Green’s Dictionary of Slang

1. an Italian, usu. used by fellow members of that race in an affectionate and congratulatory manner.

1952		(con. 1948) G. Mandel Flee the Angry Strangers 174: ‘These Italian people!’ [...] ‘Tony, the Shylock,’ Stoney said, ‘your paisan, has given me two weeks to get out.’.
1955		Boston Globe (MA) Fiction Mag. 18 Sept. 2/4: Belongs to a hombre [...] up in Anglica. Send him word paisano.
1962		S. Longstreet Flesh Peddlers (1964) 66: Maybe so, paisano.
1967		P. Thomas Down These Mean Streets (1970) 30: ‘Say, paisan,’ one guy said, ‘you even buying from us paisans, eh? Man, you must wantta be Italian.’.
1977		(con. 1960s) D. Goines Black Gangster (1991) 85: Why, paisan, the same reason we killed the old man.
1977		B. Davidson Collura (1978) 41: We’re both paisanos, kid, so if the Micks give you any trouble, let me know.
1981		(con. 1966) P. Conroy Lords of Discipline 82: I want to talk seriously to you, paisan.
1998		T. Fontana and D. Sarjeant ‘Animal Farm’ Oz ser. 2 ep. 7 [TV script] His father Nino and I were paisans. I’m Peter’s godfather.
2001		J. Stahl Plainclothes Naked (2002) 114: Since much of the local populous hailed from Italy, Edward [...] realized that he’d get more business if folks believed the neighborhood mortuary was paisano-owned.
2005		K. Huff A Steady Rain I i: Fifty guys [...] who just all happen to be a lot more ethnic than me and my bog-hopping amigo paisan over here.
2023		(con. 1962) J. Ellroy Enchanters 40: The paisans quaffed dago red.

2. a fool.

1950

in DARE.