bodybuilder vs muscle builder

bodybuilder and muscle builder both are nouns.

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

As nouns, bodybuilder and muscle builder are synonyms defined as:

bodybuilder and muscle builder: someone who does special exercises to develop a brawny musculature

Other synonyms of bodybuilder include muscle-builder, musclebuilder, muscleman.

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