A punch delivered in a semicircular motion or direction, as opposed to straight in front of the person delivering it. The boxer was caught with a vicious roundhouse punch that KO'd him on the spot. You're better off throwing quick, controlled jabs than swinging those wild roundhouses punches.

A kick delivered in a semicircular motion or direction, as opposed to straight in front of the person delivering it. The MMA fighter was knocked out after catching a roundhouse kick directly to the side of his head. She ducked beneath the roundhouse kick and countered with a devastating uppercut.