rearguard vs military

rearguard and military both are nouns.

Word	Noun	Adjective	Verb	Adverb
rearguard	Yes	No	No	No
military	Yes	Yes	No	No

rearguard (noun)	military (noun)
a detachment assigned to protect the rear of a (retreating) military body	the military forces of a nation

rearguard (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