foeman vs besieger

foeman and besieger both are nouns.

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

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

foeman: an armed adversary (especially a member of an opposing military force)
besieger: an enemy who lays siege to your position

foeman (noun)	besieger (noun)
an armed adversary (especially a member of an opposing military force)	an enemy who lays siege to your position
	an energetic petitioner