illustrator vs artist

illustrator and artist both are nouns.

Word	Noun	Adjective	Verb	Adverb
illustrator	Yes	No	No	No
artist	Yes	No	No	No

As nouns, artist is a hypernym of illustrator; that is, artist is a word with a broader meaning than illustrator:

illustrator: an artist who makes illustrations (for books or magazines or advertisements etc.)
artist: a person whose creative work shows sensitivity and imagination

Other hypernyms of illustrator include creative person.

illustrator (noun)	artist (noun)
an artist who makes illustrations (for books or magazines or advertisements etc.)	a person whose creative work shows sensitivity and imagination