Green’s Dictionary of Slang

1. an inept, incompetent person.

1937		A. Kober Having Wonderful Time (1975) [play script] 83: Don’t go ’way. I’ll be right back after I give schmiggeggie here a work-out.
1968		see sense 2.
1984		E. Ritter Urban Scrawl 155: Such a schmegegge you don’t need, am I right?
1988		J. Markus Amer. Rose 54: He develops his concept of the shmegegge. Any jerk who glides along blithely on the top of things.
1991		J. Rudeman Joseph Heller 141: Not only the nebbish, but the schlemiel, the schlimazel, the schmendrick, schmuck, narr, schnook, nudnik, schlep, trombenik, yold, schmegegge, schlump, and so on.
2000		S. Isaacs Almost Paradise 475: Who are you talking to, some schmegegge who’s never seen one of your contracts?

2. an unpleasant, petty person.

1968		L. Rosten Joys of Yiddish 353: Shmegegge, [...] Ameridish slang. Origin: unknown; probably, a dazzling onomatopoetic child of the Lower East Side. 1. An unadmirable, petty person. 2. A maladroit, untalented type. 3. A sycophant, a shlepper, a whiner, a drip.
1983		R. Price Breaks 65: I started to laugh. What a shmegeg.

3. a sycophant, a toady.

1968

see sense 2.

4. nonsense.

1968

L. Rosten Joys of Yiddish 353: Shmegegge, [...] .a lot of ‘hot air’, ‘baloney’, a cockamamy story.