A contravention is the act of doing something a law or a rule does not allow. You meet this word in the news, in court papers, and on official notices, not around the dinner table. The usual shape is “in contravention of” — in contravention of the speed limit, in contravention of school rules, in contravention of an agreement. It names the breaking as a legal fact, not as a story about a naughty person. Though actually, in ordinary talk we almost never reach for it. We say someone broke the law, went against the rules, or was not allowed to do that. “Contravention” is cooler and more official than those everyday words, and a little broader than “crime”: you can be in contravention of a quiet regulation, a sports rule, or a contract, not only a big criminal law. One contravention can be small; the word does not tell you how serious it was, only that a line was crossed.