military art vs genre

military art and genre both are nouns.

Word	Noun	Adjective	Verb	Adverb
military art	Yes	No	No	No
genre	Yes	No	No	No

As nouns, genre is a hypernym of military art; that is, genre is a word with a broader meaning than military art:

military art: the genre of art depicting military themes.
genre: a class of art (or artistic endeavor) having a characteristic form or technique

military art (noun)	genre (noun)
the genre of art depicting military themes.	a class of art (or artistic endeavor) having a characteristic form or technique
	a kind of literary or artistic work
	a style of expressing yourself in writing