illicit
1. [ adjective ] (sexuality) contrary to accepted morality (especially sexual morality) or convention
Examples:

"an illicit association with his secretary"

Related terms: licit adulterous unlawful
2. [ adjective ] (law) contrary to or forbidden by law
Synonyms: illegitimate unlawful outlawed outlaw
Examples:

"an illegitimate seizure of power" "illicit trade" "an outlaw strike" "unlawful measures"

Related terms: illegal
Similar spelling:   illicitly