From Yiddish, rendered chicken or goose fat. in east European cooking chicken fat is used as an easy fix to otherwise tasteless cooking. in other words, its a Crowd pleaser.
in jewish slang, Schmalts refers to a tacky, overdone or outright exploitative piece of art or design.
Goyim: hi man, have you seen that food-porn video where they use lard in a matzo-ball soup? i thoughtyou guys don't eat pork.
jew: that's just Schmaltz.