Meaning: a punch in the mouth
- Vince turned around and said, "Shut up, pal, or you'll get a knuckle sandwich to chew on."
- After he'd punched the thief, the shopkeeper said, "Knuckle sandwiches are free, loser. But you gotta pay for that stuff in your pockets."
This guy in the pub gave me a knuckle sandwich. It was really