roughneck vs muscleman

roughneck and muscleman both are nouns.

Word	Noun	Adjective	Verb	Adverb
roughneck	Yes	No	No	No
muscleman	Yes	No	No	No

As nouns, muscleman is a hyponym of roughneck; that is, muscleman is a word with a more specific, narrower meaning than roughneck:

Other hyponyms of roughneck include bullyboy, muscle, skin, skinhead, plug-ugly, tough guy.

roughneck (noun)	muscleman (noun)
a cruel and brutal fellow	a bully employed as a thug or bodyguard
	someone who does special exercises to develop a brawny musculature