1. (a.) Guilty of, or given to, adultery; pertaining to adultery; illicit.

2. (a.) Characterized by adulteration; spurious.

actionable adulterous against the law anarchic anarchistic anomic back-door banned barred black-market bootleg chargeable clandestine contraband contrary to law criminal extramarital felonious flawed forbade forbid forbidden freeloving furtive illegal illegitimate impermissible improper incestuous irregular justiciable lawless nonconstitutional nonlegal nonlicit nonpermissible not permitted off limits out of bounds outlaw outlawed prohibited punishable ruled out secret sneaky taboo tabooed triable unallowed unauthorized unconstitutional under the ban under-the-counter under-the-table underhanded unlawful unlicensed unofficial unpermissible unsanctioned unstatutory untouchable unwarrantable unwarranted verboten vetoed wrong wrongful