The arakh is the standard weapon used by Dothraki warriors. It has a crescent moon-shaped, curved blade about two and a half feet long and a thick handle almost the same length, making it half-sword and half-scythe. Although unable to penetrate armor, the arakh gives the wielder tremendous maneuverability of wrists.
Jorah Mormont notes that while the sweeping blade is effective and indeed necessary for a warrior on horseback, the arakh pales in comparison to the Westerosi double-edged sword for battling without a mount or at penetrating armor.
Although a Dothraki weapon, it is occasionally used by non-Dothraki, such as the mercenary captain Daario Naharis.