authority vs uncertain

authority is a noun but uncertain is not a noun.

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

authority (noun)	uncertain (noun)
the power or right to give orders or make decisions
official permission or approval
freedom from doubt; belief in yourself and your abilities
an authoritative written work
an administrative unit of government
an expert whose views are taken as definitive
(usually plural) persons who exercise (administrative) control over others

authority (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