停手 is a separable verb (离合词) meaning 'to stop doing something', often used for physical actions like hitting, fighting, or any ongoing activity that involves your hands. The verb and object can split: you can insert aspect markers like 了 or 过 between 停 and 手, as in 停了手 ('stopped one's hand'). It's commonly used in commands or narratives to tell someone to cease an action.