protester vs objector

protester and objector both are nouns.

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

As nouns, protester and objector are synonyms defined as:

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

Other synonyms of protester include contestant, dissenter, dissident.

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