theater of operations vs military

theater of operations and military both are nouns.

Word	Noun	Adjective	Verb	Adverb
theater of operations	Yes	No	No	No
military	Yes	Yes	No	No

theater of operations (noun)	military (noun)
a region in which active military operations are in progress	the military forces of a nation

theater of operations (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