"If you have the courage."
A duel was an event where two or more opponents agree to engage in combat against each other. One who participated in a duel was called a duelist. The victor was often the one who was unscathed or generally in a better position than the opponent at the end of the event. Some duels were to the death. Duels were also common with other species, including the Andorian Ushaan , the Vulcan Kal-if-fee and most notably the Klingon Right of Vengeance. (ENT: "United"; TOS: "Amok Time"; TNG: "Reunion", "The Nth Degree", "Redemption II"; VOY: "Blood Fever")
In 2399 on Vashti, the former Romulan Senator Tenqem Adrev challenged Jean-Luc Picard to a duel outside the Romulan Social Club. Though Picard parried Adrev's first thrust, he then threw his sword aside and refused to fight further. The duel was ended by Elnor, who offered Adrev a chance to back down and slew him when he refused. (PIC: "Absolute Candor")