contralto vs vocalist

contralto and vocalist both are nouns.

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

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

Other hypernyms of contralto include singer, vocaliser, vocalizer.

contralto (noun)	vocalist (noun)
the lowest female singing voice	a person who sings
a woman singer having a contralto voice

contralto (adjective)	vocalist (adjective)
of or being the lowest female voice