black, caliginous, dark, darkened, darkish, darkling, darksome, dim, dimmed, dusk, dusky, gloomy, lightless, murky, obscure, obscured, pitch-black, pitch-dark, pitchy, rayless, somber (or sombre), stygian, tenebrific, unlit

black, bleak, cheerless, chill, Cimmerian, cloudy, cold, comfortless, dark, darkening, depressing, depressive, desolate, dire, disconsolate, dismal, drear, dreary, dreich [chiefly Scottish], elegiac (also elegiacal), forlorn, funereal, gloomy, glum, godforsaken, gray (also grey), lonely, lonesome, lugubrious, miserable, morbid, morose, murky, plutonian, saturnine, sepulchral, solemn, somber (or sombre), sullen, sunless, tenebrific, wretched