castrato vs vocalist

castrato and vocalist both are nouns.

Word	Noun	Adjective	Verb	Adverb
castrato	Yes	No	No	No
vocalist	Yes	No	No	No

As nouns, vocalist is a hypernym of castrato; that is, vocalist is a word with a broader meaning than castrato:

castrato: a male singer who was castrated before puberty and retains a soprano or alto voice
vocalist: a person who sings

Other hypernyms of castrato include singer, vocaliser, vocalizer.

castrato (noun)	vocalist (noun)
a male singer who was castrated before puberty and retains a soprano or alto voice	a person who sings