The Chinese idiom **无动于衷 (wú dòng yú zhōng)** is formed through a classical grammatical structure where **无动** means "not moved" or "unmoved," and **于衷** literally translates to "within the heart" or "from one's inner feelings." Thus, the phrase literally reads as "not moved within the heart," figuratively conveying a state of complete indifference, apathy, or remaining untouched and unaffected by something emotionally. It is a fixed, expressive compound that vividly encapsulates an internal lack of emotional response.