prima donna vs opera star

prima donna and opera star both are nouns.

Word	Noun	Adjective	Verb	Adverb
prima donna	Yes	No	No	No
opera star	Yes	No	No	No

As nouns, opera star is a hypernym of prima donna; that is, opera star is a word with a broader meaning than prima donna:

Other hypernyms of prima donna include operatic star.

prima donna (noun)	opera star (noun)
a distinguished female operatic singer; a female operatic star	singer of lead role in an opera
a vain and temperamental person