supremacist vs proponent

supremacist and proponent both are nouns.

Word	Noun	Adjective	Verb	Adverb
supremacist	Yes	No	No	No
proponent	Yes	No	No	No

As nouns, proponent is a hypernym of supremacist; that is, proponent is a word with a broader meaning than supremacist:

supremacist: a person who advocates the supremacy of some particular group or racial group over all others
proponent: a person who pleads for a cause or propounds an idea

Other hypernyms of supremacist include advocate, advocator, exponent.

supremacist (noun)	proponent (noun)
a person who advocates the supremacy of some particular group or racial group over all others	a person who pleads for a cause or propounds an idea