character actor vs histrion

character actor and histrion both are nouns.

Word	Noun	Adjective	Verb	Adverb
character actor	Yes	No	No	No
histrion	Yes	No	No	No

As nouns, histrion is a hypernym of character actor; that is, histrion is a word with a broader meaning than character actor:

Other hypernyms of character actor include actor, player, role player, thespian.

character actor (noun)	histrion (noun)
an actor who specializes in playing supporting roles	a theatrical performer