militiaman vs Minuteman

militiaman and Minuteman both are nouns.

Word	Noun	Adjective	Verb	Adverb
militiaman	Yes	No	No	No
Minuteman	Yes	No	No	No

As nouns, Minuteman is a hyponym of militiaman; that is, Minuteman is a word with a more specific, narrower meaning than militiaman:

militiaman: a member of the militia; serves only during emergencies
Minuteman: an American militiaman prior to and during the American Revolution

Other hyponyms of militiaman include trainbandsman.

militiaman (noun)	Minuteman (noun)
a member of the militia; serves only during emergencies	a strategic weapon system using a guided missile of intercontinental range; missiles are equipped with nuclear warheads and dispersed in hardened silos
	an American militiaman prior to and during the American Revolution