adjective
somber
SAHM-ber/ˈsɑmbər/
Dark and subdued in tone.
An adult in a dark coat looks somber under the rainy sky.

Etymology
French sombre supplies the image of darkness or gloom. English first applied the word to places and landscapes, then extended that shadowy quality to feelings and moods.
In context
the mood was somber and pervaded by anxiety – what sociologists call ‘existential angst’.
More examples
- The room's somber colors make it feel smaller.
- The music sets a somber mood for the ceremony.
- Her voice grows somber as she shares the sad news.
Forms
somber · somberer · somberest
somberly adverb — In a serious, subdued, or gloomy manner.
somberness noun — The quality of being dark or subdued.