military vs headquarters staff

military and headquarters staff both are nouns.

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

military (noun)	headquarters staff (noun)
the military forces of a nation	military staff stationed at headquarters

military (adjective)	headquarters staff (adjective)
associated with or performed by members of the armed services as contrasted with civilians
characteristic of or associated with soldiers or the military
of or relating to the study of the principles of warfare