opposer vs enemy

opposer and enemy both are nouns.

Word	Noun	Adjective	Verb	Adverb
opposer	Yes	No	No	No
enemy	Yes	No	No	No

As nouns, enemy is a hyponym of opposer; that is, enemy is a word with a more specific, narrower meaning than opposer:

opposer: someone who offers opposition
enemy: an armed adversary (especially a member of an opposing military force)

Other hyponyms of opposer include dueler, duelist, dueller, duellist, foe, foeman, opposition, Luddite, withstander.

opposer (noun)	enemy (noun)
someone who offers opposition	an opposing military force
	any hostile group of people
	an armed adversary (especially a member of an opposing military force)
	a personal enemy