Forbidden by established rules.
Contrary to or forbidden by law, especially criminal law.
Breaching certain enacted statutes of positive law; not lawful, not legal (cf. immoral, unethical)
Being or doing something illegally.
Being an illegal immigrant; residing in a country illegally.
Totally fictitious, and often issued on behalf of a non-existent territory or country.
An illegal immigrant.
Contraband, esp. illegal substances such as drugs.
A spy working abroad illegally and undercover, without visible ties to his or her country’s authorities.
Forbidden; unallowed