principal vs film star

principal and film star both are nouns.

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

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

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

principal (noun)	film 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)	film star (adjective)
most important element