torch singer vs vocalist

torch singer and vocalist both are nouns.

Word	Noun	Adjective	Verb	Adverb
torch singer	Yes	No	No	No
vocalist	Yes	No	No	No

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

torch singer: a singer (usually a woman) who specializes in singing torch songs
vocalist: a person who sings

Other hypernyms of torch singer include singer, vocaliser, vocalizer.

torch singer (noun)	vocalist (noun)
a singer (usually a woman) who specializes in singing torch songs	a person who sings