objector vs doer

objector and doer both are nouns.

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

As nouns, doer is a hypernym of objector; that is, doer is a word with a broader meaning than objector:

Other hypernyms of objector include actor, worker.

objector (noun)	doer (noun)
a person who dissents from some established policy	a person who acts and gets things done