ghostwriter vs writer

ghostwriter and writer both are nouns.

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

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

ghostwriter: a writer who gives the credit of authorship to someone else
writer: writes (books or stories or articles or the like) professionally (for pay)

Other hypernyms of ghostwriter include author.

ghostwriter (noun)	writer (noun)
a writer who gives the credit of authorship to someone else	writes (books or stories or articles or the like) professionally (for pay)
	a person who is able to write and has written something