A stupid and ineffectual nobody.
From Yiddish shmendrik, the name of a character in an operetta by Avrom Goldfaden (1840-1908), Father of Yiddish Theater. (Dictionary.com)
"Nice, isn't it. Go ahead, take it. Here's the thing: That schmendrick that keeps looking over here -- and that one -- he's got a gun. You gotta do, what you gotta do. Stealin'. It's a beautiful thing." (Gatorade commercial featuring Harvey Keitel urging Derek Jeter to steal second base. See it on YouTube)