yobo vs muscleman

yobo and muscleman both are nouns.

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

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

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

yobo (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