debater vs controversialist

debater and controversialist both are nouns.

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

As nouns, controversialist is a hypernym of debater; that is, controversialist is a word with a broader meaning than debater:

debater: someone who engages in debate
controversialist: a person who disputes; who is good at or enjoys controversy

Other hypernyms of debater include disputant, eristic.

debater (noun)	controversialist (noun)
someone who engages in debate	a person who disputes; who is good at or enjoys controversy