principal vs movie star

principal and movie star both are nouns.

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

As nouns, movie star is a hyponym of principal; that is, movie star is a word with a more specific, narrower meaning than principal:

Other hyponyms of principal include co-star, film star, idol, matinee idol, television star, TV star.

principal (noun)	movie star (noun)
the educator who has executive authority for a school	a star who plays leading roles in the cinema
an actor who plays a principal role
the major party to a financial transaction at a stock exchange; buys and sells for his own account
(criminal law) any person involved in a criminal offense, regardless of whether the person profits from such involvement
the original amount of a debt on which interest is calculated
capital as contrasted with the income derived from it

principal (adjective)	movie star (adjective)
most important element