movie star vs movie actor

movie star and movie actor both are nouns.

Word	Noun	Adjective	Verb	Adverb
movie star	Yes	No	No	No
movie actor	Yes	No	No	No

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

Other hypernyms of movie star include screen actor, lead, principal, star.

movie star (noun)	movie actor (noun)
a star who plays leading roles in the cinema	an actor who plays a role in a film