partner vs doer

partner and doer both are nouns.

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

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

Other hypernyms of partner include actor, worker.

partner (noun)	doer (noun)
an associate in an activity or endeavor or sphere of common interest	a person who acts and gets things done
a person's partner in marriage
a person who is a member of a partnership

partner (verb)	doer (verb)
provide with a partner
act as a partner