supremacistPronunciation: /suːˈprɛməsɪst, sjuː-/Definition of supremacist noun an advocate of the supremacy of a particular group, especially one determined by race or sex:a white supremacist adjective relating to or advocating the supremacy of a particular group:supremacist ideologiesDerivatives supremacism noun supremacist in other Oxford dictionaries Definition of supremacist in the US English dictionary