knuckle sandwich UK /ˈnʌkəl ˈsæn(d)wɪdʒ/US /ˈnʌkəl ˈsænˌ(d)wɪtʃ/ noun1 •(slang) A punch to the face, especially to the mouth.OKKIE. (Raises his fist, kissing the knuckles menacingly—follows her to bottom of steps.) How would you like a knuckle sandwich? — 1957 formsknuckle sandwiches