disbelief vs scepticism

disbelief and scepticism both are nouns.

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

As nouns, disbelief and scepticism are synonyms defined as:

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

As nouns, scepticism is a hyponym of disbelief; that is, scepticism is a word with a more specific, narrower meaning than disbelief:

Other hyponyms of disbelief include agnosticism, skepticism, atheism.

disbelief (noun)	scepticism (noun)
doubt about the truth of something	the disbelief in any claims of ultimate knowledge
a rejection of belief	doubt about the truth of something