musician vs performer

musician and performer both are nouns.

Word	Noun	Adjective	Verb	Adverb
musician	Yes	No	No	No
performer	Yes	No	No	No

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

musician: someone who plays a music as a profession
performer: an entertainer who performs a dramatic or musical work for an audience

Other hypernyms of musician include performing artist.

musician (noun)	performer (noun)
artist who composes or conducts music as a profession	an entertainer who performs a dramatic or musical work for an audience
someone who plays a music as a profession