Slang: Knuckle sandwich

Definition: A punch in the face.

Example:

1) If you don't stop bothering me, you're going to get a knuckle sandwich. 

2) Sabah gave Peter a knuckle sandwich when she caught him looking at other girls.

Etymology: A 'sandwich' is an assortment of food between two pieces of bread, and 'knuckles' are the bones in your hand. So a 'knuckle sandwich' is a fist that goes straight toward your mouth.

fonte: www.peakenglish.com