1Of water or other liquid: turbid, not clear; discoloured with matter in suspension; murky, muddy.
2Figurative and in extended use: murky, unclear; dirty.
3Specifically. Muddle-headed, confused, giddy.
4Of the sky, the weather, etc.: gloomy, dark, cloudy, troubled. Also figurative of prospects, a person's looks, etc.
Early 16th century; earliest use found in Gavin Douglas (c1476–1522), poet and bishop of Dunkeld. Perhaps a variant of drubly.