Main entry: illicit
Definition: contrary to accepted morality (especially sexual morality) or convention
Usage: an illicit association with his secretary
Antonyms: licit
Definition: sanctioned by custom or morality especially sexual morality
Antonyms: lawful
Definition: conformable to or allowed by law
Main entry: illegitimate, illicit, outlaw, outlawed, unlawful
Definition: contrary to or forbidden by law
Usage: an illegitimate seizure of power; illicit trade; an outlaw strike; unlawful measures
Antonyms: legal
Definition: established by or founded upon law or official or accepted rules