The Chinese word 抽筋 (chōujīn) is a verb-object compound formed by combining the verb 抽 (chōu), meaning "to pull" or "to contract", with the noun 筋 (jīn), meaning "tendon" or "muscle". Literally, it describes the involuntary, painful contraction or cramping of a muscle, as if the tendon is being pulled tight. Figuratively, this vivid physiological metaphor extends to describe other sudden, uncontrollable, and often awkward actions or states, such as legs cramping during swimming or even erratic, "twitchy" behavior in machines or systems.