debater vs refuter

debater and refuter both are nouns.

Word	Noun	Adjective	Verb	Adverb
debater	Yes	No	No	No
refuter	Yes	No	No	No

As nouns, refuter is a hyponym of debater; that is, refuter is a word with a more specific, narrower meaning than debater:

debater: someone who engages in debate
refuter: a debater who refutes or disproves by offering contrary evidence or argument

Other hyponyms of debater include devil's advocate, confuter, disprover, rebutter, wrangler.

debater (noun)	refuter (noun)
someone who engages in debate	a debater who refutes or disproves by offering contrary evidence or argument