Sunless means without sunlight or sunshine. A sunless day is one where thick clouds cover the sky from morning until evening, blocking out the sun completely. A sunless room might have no windows, or windows that face a narrow alley where sunlight never reaches. Deep ocean waters are sunless because light can't penetrate that far down.

The word often carries a gloomy feeling. Writers describe sunless places to create a somber mood: a sunless forest floor where only mushrooms and ferns grow, or sunless winter afternoons that make you want to stay inside by the fire. But sunless doesn't always mean depressing. Caves are sunless, and exploring them can be thrilling. Some plants and animals thrive in sunless environments, adapting to life without light.

You might also hear sunless used to describe a pale complexion, suggesting someone hasn't spent much time outdoors. A sunless tan comes from a bottle or spray rather than actual sun exposure, letting people darken their skin without the sun's harmful rays.