petitioner vs besieger

petitioner and besieger both are nouns.

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

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

Other hyponyms of petitioner include postulant, canvasser, solicitor.

petitioner (noun)	besieger (noun)
one praying humbly for something	an enemy who lays siege to your position
someone who petitions a court for redress of a grievance or recovery of a right	an energetic petitioner