authorities vs government

authorities and government both are nouns.

Word	Noun	Adjective	Verb	Adverb
authorities	Yes	No	No	No
government	Yes	No	No	No

As nouns, authorities and government are synonyms defined as:

authorities and government: the organization that is the governing authority of a political unit

Other synonyms of authorities include regime.

authorities (noun)	government (noun)
the organization that is the governing authority of a political unit	the act of governing; exercising authority
	(government) the system or form by which a community or other political unit is governed
	the study of government of states and other political units
	the organization that is the governing authority of a political unit