Of mist, fog, smoke, etc.: Having the component particles densely aggregated, so as to intercept or hinder vision. Hence of the weather, etc…

Dark, gloomy, deficient in light. Of air: obscured or darkened, esp. by mist or fog. Of mist: dense, thick. Obsolete.

Dense, thick. (Often with mixture of the sense of branch A. IV.) of air, vapour, darkness. archaic or poetic.

Of the weather or the sky: ‘Thick’, ‘dirty’.

Physically agitated; of the sea, sky, etc., stormy; of water, wine, etc., stirred up so as to diffuse the sediment, made thick or muddy, turbid.