烟雾 (yān wù) literally combines 烟 (yān), meaning 'smoke'—typically from burning materials—and 雾 (wù), meaning 'fog' or 'mist', a natural atmospheric phenomenon. Together, they form a compound noun describing a hazy, cloudy mixture in the air that reduces visibility. While it can refer to literal smoke mixed with fog (e.g., industrial emissions on a humid day), it’s often used more broadly for any dense, obscuring airborne haze—including pollution-induced smog, forest fire smoke, or even theatrical stage effects.

The term carries neutral-to-slightly-negative connotations depending on context: in environmental discussions, it commonly signals air pollution or health hazards; in literature or film, it may evoke mystery or atmosphere. It is not used for light steam or vapor (e.g., from boiling water), which would be 水汽 (shuǐqì) or 蒸汽 (zhēngqì). 烟雾 is always a single lexical unit—it does not function as a phrase where the two characters can be separated or modified independently.