piano player vs musician

piano player and musician both are nouns.

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

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

Other hypernyms of piano player include instrumentalist, player.

piano player (noun)	musician (noun)
a person who plays the piano	artist who composes or conducts music as a profession
	someone who plays a music as a profession