nebulous

Etymology

Inherited from Middle English nebulous, which came from Middle French nebuleus, from Latin nebulōsus (“full of mist, foggy, cloudy”), from nebula (“mist, vapour, cloud”), from Proto-Indo-European *nébʰos (“cloud, vapor, fog, moist, sky”). By surface analysis it is nebula + -ous; see also neveling, nuel. It is cognate with Ancient Greek νέφος (néphos, “cloud”), German Nebel (from Old High German nebul, “cloud, fog”), and Old English nifol, neowol (“dark, gloomy, obscure, precipitous, prone”).