ham actor vs role player

ham actor and role player both are nouns.

Word	Noun	Adjective	Verb	Adverb
ham actor	Yes	No	No	No
role player	Yes	No	No	No

As nouns, role player is a hypernym of ham actor; that is, role player is a word with a broader meaning than ham actor:

Other hypernyms of ham actor include actor, histrion, player, thespian.

ham actor (noun)	role player (noun)
an unskilled actor who overacts	a theatrical performer
	a person who makes deceitful pretenses