contester vs controversialist

contester and controversialist both are nouns.

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

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

contester: someone who contests an outcome (of a race or an election etc.)
controversialist: a person who disputes; who is good at or enjoys controversy

Other hypernyms of contester include disputant, eristic.

contester (noun)	controversialist (noun)
someone who contests an outcome (of a race or an election etc.)	a person who disputes; who is good at or enjoys controversy