self-confidence vs uncertain

self-confidence is a noun but uncertain is not a noun.

Word	Noun	Adjective	Verb	Adverb
self-confidence	Yes	No	No	No
uncertain	No	Yes	No	No

self-confidence (noun)	uncertain (noun)
freedom from doubt; belief in yourself and your abilities

self-confidence (adjective)	uncertain (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