novelist vs writer

novelist and writer both are nouns.

Word	Noun	Adjective	Verb	Adverb
novelist	Yes	No	No	No
writer	Yes	No	No	No

As nouns, writer is a hypernym of novelist; that is, writer is a word with a broader meaning than novelist:

novelist: one who writes novels
writer: writes (books or stories or articles or the like) professionally (for pay)

Other hypernyms of novelist include author.

novelist (noun)	writer (noun)
one who writes novels	writes (books or stories or articles or the like) professionally (for pay)
	a person who is able to write and has written something