Windelweich

"Soft as a diaper" (the literal translation of "windelweich") sounds like an ad for mattresses, cotton balls or toilet paper. But no, there's nothing soft, gentle and baby-like about this word, which is most often used together with the somewhat harsher word "verprügeln" ("to beat up"). So if someone tells you they're going to "windelweich verprügeln" you, you'd better run. Chances are your face will be as soft as a diaper after they've finished with you.