muscle-builder vs worker

muscle-builder and worker both are nouns.

Word	Noun	Adjective	Verb	Adverb
muscle-builder	Yes	No	No	No
worker	Yes	No	No	No

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

muscle-builder: someone who does special exercises to develop a brawny musculature
worker: a person who acts and gets things done

Other hypernyms of muscle-builder include actor, doer.

muscle-builder (noun)	worker (noun)
someone who does special exercises to develop a brawny musculature	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