look-alike vs worker

look-alike and worker both are nouns.

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

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

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

Other hypernyms of look-alike include actor, doer.

look-alike (noun)	worker (noun)
someone who closely resembles a famous person (especially an actor)	sterile member of a colony of social insects that forages for food and cares for the larvae
	a person who works at a specific occupation
	a member of the working class (not necessarily employed)
	a person who acts and gets things done

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