illegal

Forms

1.Contrary to, forbidden, or not authorized by law, especially criminal law.
- It's illegal to go over 70mph on any British road, so why should drivers have cars that can?
- This is illegal, you know!
- Major parties have long relied on large-scale campaign contributions, and the LDP was only recently mired in an illegal fundraising scandal. Sanseito drew its support from smaller, individual donations.
2.Forbidden by established rules.
- Moving a pawn backward is an illegal move in chess.
- The computer program performed an illegal operation and was terminated.
3.Totally fictitious, and often issued on behalf of a non-existent territory or country.
4.Being or doing something illegally.(offensive)

1.A spy operating abroad illegally and under non-official cover, without visible ties to his or her country’s authorities.
2.Contraband, esp. illegal substances such as drugs.(colloquial)
3.Ellipsis of illegal immigrant.(colloquial)
- In Manchester and in Aldershot in Hampshire, asylum seeker accommodation was targeted by demonstrators carrying placards that read “deport them, don’t support them” and “no apartments for illegals”.

Common· #1936

Borrowed from French illégal, from Medieval Latin illegalis, from Latin legalis, by surface analysis, il- + legal.

In senses relating to immigration, via clipping of illegal alien or illegal immigrant.