incredulity vs disbelief

incredulity and disbelief both are nouns.

Word	Noun	Adjective	Verb	Adverb
incredulity	Yes	No	No	No
disbelief	Yes	No	No	No

As nouns, incredulity and disbelief are synonyms defined as:

Other synonyms of incredulity include mental rejection, scepticism, skepticism.

incredulity (noun)	disbelief (noun)
doubt about the truth of something	doubt about the truth of something
	a rejection of belief