rock star vs vocaliser

rock star and vocaliser both are nouns.

Word	Noun	Adjective	Verb	Adverb
rock star	Yes	No	No	No
vocaliser	Yes	No	No	No

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

Other hypernyms of rock star include rock 'n' roll musician, rocker, singer, vocalist, vocalizer.

rock star (noun)	vocaliser (noun)
a famous singer of rock music	a person who sings
	an organism that can utter vocal sounds