adjective
1.
Synonyms: dark 1, caliginous, dim, dusk, dusky, gloomy, lightless, murky, obscure, tenebrous
2.
Synonyms: gloomy 3, black, bleak, depressing, depressive, dismal, dispiriting, dreary, funereal, tenebrific
3.
Synonyms: serious 1, earnest, grave, no-nonsense, sedate, sober, sobersided, solemn, staid, weighty
Idioms: as somber as an undertaker