duel vs struggle

duel and struggle both are nouns.

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

As nouns, struggle is a hypernym of duel; that is, struggle is a word with a broader meaning than duel:

Other hypernyms of duel include battle.

As verbs, struggle is a hypernym of duel; that is, struggle is a word with a broader meaning than duel:

Other hypernyms of duel include contend, fight.

duel (noun)	struggle (noun)
a prearranged fight with deadly weapons by two people (accompanied by seconds) in order to settle a quarrel over a point of honor	strenuous effort
any struggle between two skillful opponents (individuals or groups)	an energetic attempt to achieve something
	an open clash between two opposing groups (or individuals)

duel (verb)	struggle (verb)
fight a duel, as over one's honor or a woman	be engaged in a fight; carry on a fight
	to exert strenuous effort against opposition
	climb awkwardly, as if by scrambling
	make a strenuous or labored effort