Forfeit means to lose or give up something, usually as a penalty. If you don’t finish your homework and eat all your broccoli, you'll most likely forfeit your right to watch TV before going to bed.
An adjective, noun, and verb all rolled into one, forfeit came into existence around 1300 meaning “to lose by misconduct.” To forfeit is to lose or give up something as punishment for making an error. A forfeit is what is lost. You've probably heard of forfeiting a game or match — like when you don't show up with enough players or pick one too many fights with the opposing team.