contributor vs writer

contributor and writer both are nouns.

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

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

contributor: a writer whose work is published in a newspaper or magazine or as part of a book
writer: writes (books or stories or articles or the like) professionally (for pay)

Other hypernyms of contributor include author.

contributor (noun)	writer (noun)
someone who contributes (or promises to contribute) a sum of money	writes (books or stories or articles or the like) professionally (for pay)
a writer whose work is published in a newspaper or magazine or as part of a book	a person who is able to write and has written something