The kopis was a one-handed, single-edged sword about 3 feet in length, with the blade curving forward and widening near the tip. The blade has a reinforced spine to give it greater strength and durability, and the hilt's wrap-around grip made the sword less likely to slip out of the user's hand in the heat of battle.

The Kopis was primarily a slashing weapon. The Kopis was even used to cut meat. While most Greek infantry, such as the Spartan hoplite, favored the shorter, more martially versatile xiphos, the Kopis found favor with mounted forces, as its downward curve made it highly suitable for cavalry.