Stories We Like: A Guide to the Comma
1948, probably from Yiddish shnuk "elephant's trunk," or altered from schmuck (q.v.), or perhaps from German schnucke "a small sheep," used in U.S. Yiddish for "a customer easily persuaded, a sucker."
An ineffectual person; a naive person often victimized; patsy • A more affectionate and compassionate way of designating a schlemiel: Don't be such an apologetic schnook
[1940s+; fr American-Yiddish shnook, said to be fr German Schnucke, ''small sheep''; probably related to the pet names snooks, snookums, etc]