The word **垂死** (chuísǐ), meaning "moribund" or "on the brink of death," is a classical Chinese compound formed through metaphorical semantic combination: the character **垂** means "to hang down" or "to be nearing" (a state), implying decline and immediacy, while **死** means "death," so together they create a vivid image of "hanging on the edge of death" or "descending into death," effectively conveying a state of extreme weakness and fatal proximity rather than a literal description.