(n.) An invisible, noxious emanation, as of vapor or gas; as, the effluvium from diseased bodies\, or from ill drainage.

afterdamp aroma aura blackdamp breath chokedamp cloud coal gas damp definite odor detectable odor ectoplasm ectoplasy emanation essence exhalation exhaust exhaust gas exteriorized protoplasm fetid air firedamp flatus flavor fluid fragrance fume malaria mephitis miasma odor puff of smoke redolence reek savor scent smell smoke smudge spoor steam stench subtle odor trace trail vapor volatile water vapor whiff