accompanyist vs instrumentalist

accompanyist and instrumentalist both are nouns.

Word	Noun	Adjective	Verb	Adverb
accompanyist	Yes	No	No	No
instrumentalist	Yes	No	No	No

As nouns, instrumentalist is a hypernym of accompanyist; that is, instrumentalist is a word with a broader meaning than accompanyist:

accompanyist: a person who provides musical accompaniment (usually on a piano)
instrumentalist: someone who plays a music as a profession

Other hypernyms of accompanyist include musician, player.

accompanyist (noun)	instrumentalist (noun)
a person who provides musical accompaniment (usually on a piano)	someone who plays a music as a profession