muscle-builder vs muscle builder

muscle-builder and muscle builder both are nouns.

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

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

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

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

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