Added 9 October 2026 booster /ˈbustɚ/ noun Categories: PeopleThingsRare Words noun ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about booster at Wordnik → Where our words come from → A person who backs a politician or a team etc. all their supporters came out for the game Someone who is an active supporter and advocate. A thief who steals goods that are in a store. Related Words: championpromotersupporterprotagonistpluggershoplifterfriendadmirer Back to today's word