‘Yī shēn’ literally combines ‘yī’ (one) and ‘shēn’ (body), forming a measure phrase meaning ‘a full body of’—used to describe something covering or affecting the entire body, especially sweat, clothes, fragrance, or dirt. It functions as a noun phrase, not a quantifier for clothing items themselves, but rather for the state or condition *on* the body.

This expression is common in descriptive, everyday speech—especially when emphasizing intensity or completeness: ‘yī shēn hàn’ (a full body of sweat), ‘yī shēn yīfu’ (a full set/outfit of clothes), or ‘yī shēn xiāngwèi’ (a full-body fragrance). It’s neutral in register and frequently appears in both spoken and written Chinese, particularly in narratives, weather descriptions, or personal accounts.