BJS vs government agency

BJS and government agency both are nouns.

Word	Noun	Adjective	Verb	Adverb
BJS	Yes	No	No	No
government agency	Yes	No	No	No

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

BJS: the agency in the Department of Justice that is the primary source of criminal justice statistics for federal and local policy makers
government agency: an administrative unit of government

Other hypernyms of BJS include agency, authority, bureau, federal agency, office.

BJS (noun)	government agency (noun)
the agency in the Department of Justice that is the primary source of criminal justice statistics for federal and local policy makers	an administrative unit of government