1760 "gloomy, shadowy" (earlier sombrous, c. 1730), from French sombre "dark, gloomy," from Old French sombre (14c.), from an adjective from Late Latin subumbrare "to shadow," from sub "under" (see sub-) + umbra "shade, shadow," perhaps from a suffixed form of PIE *andho- "blind, dark" (see umbrage). Related: Somberly; somberness.