muscle builder vs doer

muscle builder and doer both are nouns.

Word	Noun	Adjective	Verb	Adverb
muscle builder	Yes	No	No	No
doer	Yes	No	No	No

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

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

Other hypernyms of muscle builder include actor, worker.

muscle builder (noun)	doer (noun)
someone who does special exercises to develop a brawny musculature	a person who acts and gets things done