uncertain vs certainty

uncertain is not a noun while certainty is a noun.

Word	Noun	Adjective	Verb	Adverb
uncertain	No	Yes	No	No
certainty	Yes	No	No	No

uncertain (noun)	certainty (noun)
	something that is certain
	the state of being certain

uncertain (adjective)	certainty (adjective)
not established beyond doubt; still undecided or unknown
lacking or indicating lack of confidence or assurance
not certain to occur; not inevitable
not established or confirmed
ambiguous (especially in the negative)
not consistent or dependable
subject to change