muscleman vs ruffian

muscleman and ruffian both are nouns.

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

As nouns, ruffian is a hypernym of muscleman; that is, ruffian is a word with a broader meaning than muscleman:

Other hypernyms of muscleman include bully, hooligan, roughneck, rowdy, tough, yob, yobbo, yobo.

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