The word 报复 is formed by combining two characters, each contributing a core idea to create a unified concept. The first character, 报 (bào), carries the inherent meaning of repaying or responding to an action, often with a sense of requital. The second, 复 (fù), introduces the notion of repetition, return, or a reciprocal action. When fused, they conceptually depict the act of "paying back" an injury or wrong, a retaliatory response that returns a negative action to its originator, thus forming the complete idea of "revenge" or "retaliation".