‘赤膊’ literally combines 赤 (chì), meaning ‘red’ or ‘bare, naked’, and 膊 (bó), meaning ‘upper arm’ or ‘shoulder’. Together, it describes the state of having bare arms—typically with the shirt removed or sleeves rolled up high, exposing the shoulders and upper arms. It emphasizes physical exposure rather than just sleeveless clothing; someone wearing a sleeveless T-shirt is not usually described as 赤膊, but a man removing his shirt to cool down or work hard might be.

The term carries informal, often masculine connotations and appears frequently in descriptions of manual labor, sports, hot-weather behavior, or casual street scenes. It can also imply effort, intensity, or rawness—e.g., ‘赤膊上阵’ (to go into battle bare-armed) is an idiom meaning to confront a challenge directly and without reserve. While neutral in basic usage, context may add connotations of ruggedness, informality, or even impropriety in formal settings.