som·ber 
(sŏmbər)
(sŏmbər)adj.
1.
a. Dark; gloomy: a somber room.
b. Dull or dark in color: somber hues.
2.
a. Melancholy; dismal: a somber mood.
b. Serious; grave: a somber spokesperson.
[French sombre, from Old French, from *sombrer, to cast a shadow, from Late Latin subumbrāre, from Latin sub umbrā, in shadow : sub, under; see SUB- + umbrā, ablative of umbra, shadow.]
somber·ly adv.
somber·ness n.