military headquarters vs HQ

military headquarters and HQ both are nouns.

Word	Noun	Adjective	Verb	Adverb
military headquarters	Yes	No	No	No
HQ	Yes	No	No	No

As nouns, military headquarters and HQ are synonyms defined as:

military headquarters and HQ: the military installation from which a commander performs the functions of command

Other synonyms of military headquarters include headquarters.

military headquarters (noun)	HQ (noun)
the military installation from which a commander performs the functions of command	the military installation from which a commander performs the functions of command