adversary vs foeman

adversary and foeman both are nouns.

Word	Noun	Adjective	Verb	Adverb
adversary	Yes	No	No	No
foeman	Yes	No	No	No

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

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

Other hyponyms of adversary include dueler, duelist, dueller, duellist, enemy, foe, opposition, Luddite, withstander.

adversary (noun)	foeman (noun)
someone who offers opposition	an armed adversary (especially a member of an opposing military force)