government building vs edifice

government building and edifice both are nouns.

Word	Noun	Adjective	Verb	Adverb
government building	Yes	No	No	No
edifice	Yes	No	No	No

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

government building: a building that houses a branch of government
edifice: a structure that has a roof and walls and stands more or less permanently in one place

Other hypernyms of government building include building.

government building (noun)	edifice (noun)
a building that houses a branch of government	a structure that has a roof and walls and stands more or less permanently in one place