simple.wiktionary.orgopponent - Simple English WiktionaryPronunciation[change] IPA (key): /əˈpəʊnənt/ Audio (UK)(file) Noun[change] Singular opponent Plural opponents (countable) An opponent is someone who is not in your team in a game, an opposite team. Synonym: rival (countable) Someone that objects to something. The United Nations is an opponent of the possession of child pornography.