certainty vs authority

certainty and authority both are nouns.

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

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

certainty (noun)	authority (noun)
something that is certain	the power or right to give orders or make decisions
the state of being certain	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