Contravene is from Late Latin contravenire ('to come against, oppose'), from Latin contra ('against') + venire ('to come'). The ancestry passes through Latin contravenire, Latin venire, and Proto-Indo-European *gwem-. The prefix contra contributes the sense of opposition or againstness, helping to explain the word's surface structure. In present use as a verb, it means "to act in violation of a law, rule, or principle", keeping the historical formation close to the word's ordinary semantic work. Related words include intervene, convene, prevent, and venue; derived forms include contravention and contravener.