contributor vs bestower

contributor and bestower both are nouns.

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

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

contributor: someone who contributes (or promises to contribute) a sum of money
bestower: person who makes a gift of property

Other hypernyms of contributor include conferrer, donor, giver, presenter.

contributor (noun)	bestower (noun)
someone who contributes (or promises to contribute) a sum of money	person who makes a gift of property
a writer whose work is published in a newspaper or magazine or as part of a book