The word 冲动 is formed by combining two characters, each contributing a core action-oriented concept. 冲 (chōng) carries the idea of rushing forward, dashing, or surging, like water or a force. 动 (dòng) means to move, to act, or to set in motion. When merged, they create a composite concept where an inner surge or rush compels movement or action, perfectly encapsulating the meaning of "impulse", a sudden, powerful urge to act.