1. (a.) Guilty of crime or sin.

2. (a.) Involving a crime; of the nature of a crime; -- said of an act or of conduct; as, criminal carelessness.

3. (a.) Relating to crime; -- opposed to civil; as, the criminal code.

4. (n.) One who has committed a crime; especially, one who is found guilty by verdict, confession, or proof; a malefactor; a felon.