protester vs contestant

protester and contestant both are nouns.

Word	Noun	Adjective	Verb	Adverb
protester	Yes	No	No	No
contestant	Yes	No	No	No

As nouns, protester and contestant are synonyms defined as:

protester and contestant: a person who dissents from some established policy

Other synonyms of protester include dissenter, dissident, objector.

protester (noun)	contestant (noun)
someone who participates in a public display of group feeling	a person who participates in competitions
a person who dissents from some established policy	a person who dissents from some established policy