besieger vs foe

besieger and foe both are nouns.

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

As nouns, foe is a hypernym of besieger; that is, foe is a word with a broader meaning than besieger:

Other hypernyms of besieger include enemy, foeman, opposition.

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