ONI vs federal agency

ONI and federal agency both are nouns.

Word	Noun	Adjective	Verb	Adverb
ONI	Yes	No	No	No
federal agency	Yes	No	No	No

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

ONI: the military intelligence agency that provides for the intelligence and counterintelligence and investigative and security requirements of the United States Navy
federal agency: an administrative unit of government

Other hypernyms of ONI include agency, authority, bureau, government agency, office.

ONI (noun)	federal agency (noun)
the military intelligence agency that provides for the intelligence and counterintelligence and investigative and security requirements of the United States Navy	an administrative unit of government