The Chinese word **叹气 (tànqì)**, meaning "to sigh," is a compound verb formed through semantic combination. The first character, **叹 (tàn)**, originally depicted a mouth and meant "to sigh" or "lament." The second character, **气 (qì)**, signifies "air" or "breath." When combined, the term literally depicts the action of "emitting a sigh of breath," perfectly capturing the physical and emotional act of releasing a deep, often regretful or resigned, breath. Thus, the word's formation logically merges the action (叹) with its essential medium (气) to create a vivid, onomatopoeic expression.