From Longman Dictionary of Contemporary Englishpartygoerpar‧ty‧go‧er /ˈpɑːtiˌɡəʊə $ ˈpɑːrtiˌɡoʊər/ noun [countable] someone who is at a party young partygoers
Examples from the Corpus
partygoer• As well as a cooked meal, each partygoer was invited to tour the factory and visit their former workplaces and old friends.• They proceeded to apprehend Willis and a fellow partygoer and dragged them screaming and kicking to the squad car. 