Foolish or contemptible people (plural); a Yiddish insult meaning an annoying jerk.
From Yiddish 'shmok,' borrowed from Hebrew 'shmok' (penis). The Yiddish insult arrived in American English through Jewish immigrants, 1950s-60s.
Yiddish insults are brutally creative because they're often anatomically specific—'schmuck,' 'putz,' 'schlong' all reference body parts as stupid—and when these words entered American English they kept their sharp bite even as their literal meanings faded, making them perfect all-purpose insults.
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