flag officer vs military

flag officer and military both are nouns.

Word	Noun	Adjective	Verb	Adverb
flag officer	Yes	No	No	No
military	Yes	Yes	No	No

flag officer (noun)	military (noun)
a senior naval officer above the rank of captain	the military forces of a nation

flag officer (adjective)	military (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