military government vs regime

military government and regime both are nouns.

Word	Noun	Adjective	Verb	Adverb
military government	Yes	No	No	No
regime	Yes	No	No	No

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

military government: government by the military and an army
regime: the organization that is the governing authority of a political unit

Other hypernyms of military government include authorities, government.

military government (noun)	regime (noun)
government by the military and an army	(medicine) a systematic plan for therapy (often including diet)
	the organization that is the governing authority of a political unit