dueler vs duel

dueler and duel both are nouns.

Word	Noun	Adjective	Verb	Adverb
dueler	Yes	No	No	No
duel	Yes	No	Yes	No

dueler (noun)	duel (noun)
a person who fights duels	a prearranged fight with deadly weapons by two people (accompanied by seconds) in order to settle a quarrel over a point of honor
	any struggle between two skillful opponents (individuals or groups)

dueler (verb)	duel (verb)
	fight a duel, as over one's honor or a woman