separationist vs proponent

separationist and proponent both are nouns.

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

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

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

Other hypernyms of separationist include advocate, advocator, exponent.

separationist (noun)	proponent (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