music director vs musician

music director and musician both are nouns.

Word	Noun	Adjective	Verb	Adverb
music director	Yes	No	No	No
musician	Yes	No	No	No

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

music director (noun)	musician (noun)
the person who leads a musical group	artist who composes or conducts music as a profession
	someone who plays a music as a profession