selector vs doer

selector and doer both are nouns.

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

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

Other hypernyms of selector include actor, worker.

selector (noun)	doer (noun)
a switch that is used to select among alternatives	a person who acts and gets things done
a person who chooses or selects out