executive agency vs authority

executive agency and authority both are nouns.

Word	Noun	Adjective	Verb	Adverb
executive agency	Yes	No	No	No
authority	Yes	No	No	No

As nouns, authority is a hypernym of executive agency; that is, authority is a word with a broader meaning than executive agency:

Other hypernyms of executive agency include agency, bureau, federal agency, government agency, office.

executive agency (noun)	authority (noun)
an agency of the executive branch of government	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