musclebuilder vs muscle builder

musclebuilder and muscle builder both are nouns.

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

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

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

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

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