having behavior or characteristics differing from that which is normal or expected, especially in an undesirable or socially disapproved manner; as, deviant behavior.
Behaviors that are different or out of the normal range from what most people do. When applied to sexual situations, it can include a variety of sexual behaviors, however, for this glossary, we will use the term for those actions which are against the law or acceptable standards. ("Sexually molesting a child is a deviant act since most people understand that it is wrong and against the law.")