also ... schmaltz, sentimental or florid art or music (schmaltzy the more popular usage)

Literally, "schmaltz" is chicken-fat. "Schmaltzy" music or art is smooth (lots of glissandos) and oily and verging on greasy or oozing (compare "Oozing charm through every pore, he oiled his way about the floor..." describing Zoltan Karpathy - My Fair Lady).

There's a lot of allegorical derivation in the Yiddish words. "Schmuck" is German for jewelry, and it isn't hard to arrive at the "family jewels" connotation (testicles, and while that's not exactly the literal translation, it's not far from it, either).