"contemptible person," 1892, from E.Yiddish
shmok, lit. "penis," from Old Pol.
smok "grass snake, dragon." Not the same word as Ger.
schmuck "jewelry, adornments," which is related to Low Ger.
smuck "supple, tidy, trim, elegant," and related to O.N.
smjuga "slip, step through" (see
smock). In Jewish homes, the word was "regarded as so vulgar as to be taboo" [Leo Rosten, "The Joys of Yiddish," 1968] and Lenny Bruce wrote that saying it on stage got him arrested on the West Coast "by a Yiddish undercover agent who had been placed in the club several nights running to determine if my use of Yiddish terms was a cover for profanity." Euphemized as
schmoe, which was the source of Al Capp's cartoon strip creature the
schmoo.