supremacist vs advocator

supremacist and advocator both are nouns.

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

As nouns, advocator is a hypernym of supremacist; that is, advocator 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
advocator: a person who pleads for a cause or propounds an idea

Other hypernyms of supremacist include advocate, exponent, proponent.

supremacist (noun)	advocator (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