‘蹲脚’ (cūn jiǎo) is a colloquial verb meaning 'to sprain one's foot', especially through sudden twisting, overextension, or awkward landing—often during physical activity like sports, walking on uneven ground, or stepping off a curb. Despite the character 蹲 (cūn), which usually means 'to squat', here it functions phonetically and idiomatically rather than semantically; the compound is not derived from the literal meaning of squatting but has evolved as a fixed expression for foot injury.

This term is commonly used in informal spoken Mandarin, particularly in southern China and among younger speakers. It emphasizes acute, non-fracture soft-tissue injury—like ligament strain or mild joint trauma—and is distinct from more clinical terms like ‘扭伤’ (niǔ shāng) or ‘踝关节损伤’ (huái guānjié sǔnshāng). While widely understood, it’s rarely found in formal medical writing or textbooks, where standard terminology prevails.