What is the word for jealousy disguised in a disapproving remark
Not exactly jealousy, but putting down something you don't have for yourself: (or, the person who has it) in the US we call it "sour grapes" - from Aesop's fable of "The Fox and the Grapes" (where the fox couldn't get the grapes, (he really wanted) no matter how hard he tried - so he said, "They're probably sour anyway."