n. 25B6; noun
he was killed in a duel : MANO-A-MANO, single combat; fight, confrontation, head-to-head; informal face-off, shoot-out; archaic rencounter.
a snooker duel : CONTEST, match, game, meet, encounter.
25B6; verb they duelled with swords : FIGHT A DUEL, fight, battle, combat, contend.