piano player vs instrumentalist

piano player and instrumentalist both are nouns.

Word	Noun	Adjective	Verb	Adverb
piano player	Yes	No	No	No
instrumentalist	Yes	No	No	No

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

Other hypernyms of piano player include musician, player.

piano player (noun)	instrumentalist (noun)
a person who plays the piano	someone who plays a music as a profession