Illicit means unlawful or forbidden.
Illicit is an adjective.
Synonyms: unlawful, prohibited, criminal, forbidden, illegal, improper.
Antonyms: allowed, legal, legitimate, permissible, kosher, legal, licit.
The group is known to engage in illicit activities such as drug scam and steeling things.
The police tried to elicit any information that might help them stop the illicit activity.
The trafficking of illicit drugs is a serious problem in our country.