Some dude that has no real redeeming qualities about him - physical or otherwise. They generally aren't bad or ugly people, just not anything to write home about.
Yeah, you're talking about Ashley's new boyfriend? That dude is such a fucking schmoo. No idea why she likes him.
1. A weird white blob of a thing that was a cartoon in the 70's and 80's
2. fanny, pussy, use in conjuntion with a tockley, knob or even another schmoo.
Man that girls didnt have any undies on, she knew i could see and she showed me her schmoo!