National Guard vs ANG

National Guard and ANG both are nouns.

Word	Noun	Adjective	Verb	Adverb
National Guard	Yes	No	No	No
ANG	Yes	No	No	No

As nouns, ANG is a hyponym of National Guard; that is, ANG is a word with a more specific, narrower meaning than National Guard:

National Guard: United States military reserves recruited by the states and equipped by the federal government; subject to call by either
ANG: a civilian reserve component of the United States Air Force that provides prompt mobilization during war and assistance during national emergencies

Other hyponyms of National Guard include Air National Guard, Army National Guard, ARNG.

National Guard (noun)	ANG (noun)
United States military reserves recruited by the states and equipped by the federal government; subject to call by either	a civilian reserve component of the United States Air Force that provides prompt mobilization during war and assistance during national emergencies