Green’s Dictionary of Slang

a fool, a naïve or ineffectual person, esp. as a victim.

1937		A. Kober Having Wonderful Time (1975) [play script] 112: It looks as if we’re just a couple of schnooks.
1949		ref. in 1989 H. Rawson Dict. of Invective (1991) 338: By 1949, Jack Benny was using it in a more general sense on the radio: ‘Don’t be such an apologetic schnook’ (Harold Wentworth and Stuart Berg Flexner, Dictionary of American Slang, 1975).
1949		J. Archibald ‘Dying to See Willie’ in Popular Detective Mar. 🌐 That shnook couldn’t find a moose in the museum of natural history.
1952		W.R. Burnett Little Men, Big World 35: Does it look like everything’s all right, you schnook? I’m sick in bed, ain’t I?
1954		Mad mag. June 12: Such a neurotic ... such a philanderer ... such a ... such a schnook.
1956		H. Ellison ‘I’ll Bet You a Death’ in Deadly Streets (1983) 34: You takin’ cuts at schnookle Johnny Slice.
1958		Mad mag. Sept.–Oct. 6: Don’t Be A Shnook. Be Sure You’re Satisfied!
1962		S. Longstreet Flesh Peddlers (1964) 45: Money-worried shnooks make monkeys of their jobs.
1967		L. Bruce Essential Lenny Bruce 150: Schnook, don’tya remembuh me?
1974		(con. late 1940s) E. Thompson Tattoo (1977) 462: ‘Who?’ ‘That Alden schnoorp.’.
1977		C. McFadden Serial 45: He couldn’t help feeling like kind of a schnook.
1985		N. Pileggi Wiseguy (2001) 233: I’m an average nobody. I get to live the rest of my life like a shnook.
1998		D. Remnick King of the World 154: Soon just about every schnook with a microphone would be asking the day’s goat...
1999		J. Stahl Perv (2001) 36: The poor shnook figured if he had some Moms down there maybe the turd-burglars would spare his keister.
2004		Beastie Boys ‘Hey Fuck You’ 🎵 Which one of you schnooks took my rhyme book?
2017		T. Pluck badcitizencorporation.com 27 Mar. 🌐 Fairy tales that middle class shnooks whisper to each other in the dark, that if you wander out the cul-de-sac you’re gonna ‘see some shit’.
2021		J. Ellroy Widespread Panic 109: We badger-gamed businessmen [...] Babs snared the schnooks [...] I kicked the door in and played irate husband.