The meaning of illegal is not according to or authorized by law See ‘meaning & use’ for definitions, usage, and quotation evidence. Contrary to or in violation of a law
Not sanctioned by official rules (as of a game). There are six meanings listed in oed's entry for the word illegal, one of which is considered offensive Forbidden by law or statute
Not allowed by the rules of a sport An offensive word for someone… An illegal pass in football Unacceptable to or not performable by a computer
If something is illegal, the law says that it is not allowed It is illegal to intercept radio messages.illegal drugs. Definition of illegal adjective in oxford advanced learner's dictionary Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.
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. Not allowed by the law not legal Not allowed by the rules in a game