incredulity vs skepticism

incredulity and skepticism both are nouns.

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

As nouns, incredulity and skepticism are synonyms defined as:

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

incredulity (noun)	skepticism (noun)
doubt about the truth of something	doubt about the truth of something
	the disbelief in any claims of ultimate knowledge