look-alike vs doer

look-alike and doer both are nouns.

Word	Noun	Adjective	Verb	Adverb
look-alike	Yes	Yes	No	No
doer	Yes	No	No	No

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

look-alike: someone who closely resembles a famous person (especially an actor)
doer: a person who acts and gets things done

Other hypernyms of look-alike include actor, worker.

look-alike (noun)	doer (noun)
someone who closely resembles a famous person (especially an actor)	a person who acts and gets things done

look-alike (adjective)	doer (adjective)
resembling closely