One who believes that a certain group is or should be supreme.(noun)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Use "supremacist" in a sentence
"So if you believe you race is weak, how can you be described as a supremacist?"
"To me, this smacks of a kind of supremacist attitude."
"He's on record as complaining about all languages other than English being used in Cardiff, yet he manages to say Welsh speakers are 'supremacist' because they'd like two rather than one language."