Real Dictionary

forfeit
verb: If you forfeit something, you give it up willingly, especially so that you can achieve something else.
verb: If you forfeit something, you lose it or are forced to give it up because you have broken a rule or done something wrong.

forfeit in American English
lost, given up, or taken away as a forfeit
something that one loses or has to give up because of some crime, fault, or neglect of duty; specif., a fine or penalty
to lose, give up, or be deprived of as a forfeit for some crime, fault, etc.
noun: a fine; penalty

forfeit in British English
adjective: surrendered or liable to be surrendered as a penalty
noun: something lost or given up as a penalty for a fault, mistake, etc
verb: to lose or be liable to lose in consequence of a mistake, fault, etc