separatist vs advocator

separatist and advocator both are nouns.

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

As nouns, advocator is a hypernym of separatist; that is, advocator is a word with a broader meaning than separatist:

separatist: an advocate of secession or separation from a larger group (such as an established church or a national union)
advocator: a person who pleads for a cause or propounds an idea

Other hypernyms of separatist include advocate, exponent, proponent.

separatist (noun)	advocator (noun)
an advocate of secession or separation from a larger group (such as an established church or a national union)	a person who pleads for a cause or propounds an idea

separatist (adjective)	advocator (adjective)
having separated or advocating separation from another entity or policy or attitude