1.verbTo suffer the loss of something by wrongdoing or non-compliance
"He forfeited his last chance of an early release from jail by repeatedly attacking another inmate."
2.verbTo lose a contest, game, match, or other form of competition by voluntary withdrawal, by failing to attend or participate, or by violation of the rules
"Because only nine players were present, the football team was forced to forfeit the game."
3.verbTo be guilty of a misdeed; to be criminal; to transgress.
4.verbTo fail to keep an obligation.
5.nounThe act by which something is forfeited or surrendered; a giving up.