The meaning of ILLEGAL is not according to or authorized by law : contrary to or in violation of a law : unlawful, illicit; also : not sanctioned by official rules (as of a game). How to use illegal in a sentence.

ILLEGAL definition: 1. not allowed by law: 2. not allowed by the rules of a sport: 3. an offensive word for someone…. Learn more.

Dec 11, 2025 · According to Black's Law Dictionary (2nd edition), "illegal" may mean only that something lacks authority of the law or support from law (that is, that it's not legal), not that it's against the law, …

1. Prohibited by law. 2. Prohibited by official rules: an illegal pass in football. 3. Unacceptable to or not performable by a computer: an illegal operation.

If something is illegal, the law says that it is not allowed. It is illegal to intercept radio messages. Birth control was illegal there until 1978. He has been charged with membership of an illegal organisation.

Definition of illegal adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

ILLEGAL definition: forbidden by law or statute. See examples of illegal used in a sentence.

There are six meanings listed in OED's entry for the word illegal, one of which is considered offensive. See ‘Meaning & use’ for definitions, usage, and quotation evidence.

ILLEGAL meaning: 1 : not allowed by the law not legal; 2 : not allowed by the rules in a game

Something illegal is against the law or breaks the rules. If you're reading this in jail, you've probably done something illegal, and if you're not in jail, there's plenty of time to obey the law.