opener vs doer

opener and doer both are nouns.

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

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

Other hypernyms of opener include actor, worker.

opener (noun)	doer (noun)
a hand tool used for opening sealed containers (bottles or cans)	a person who acts and gets things done
the first event in a series
a person who unfastens or unwraps or opens