One who transgresses; a law-breaker; a sinner.

One who transgresses or violates a law, oath, convention, etc.

One who breaks or infringes (a bond or obligation); a violator, infringer.

A person who breaks a law, rule, promise, etc., or who fails to observe an agreement. Also: a person who fails to respect a right or privilege.

One who infringes (in the various senses of the verb); a violator.

One who contravenes.