Stygian

a.

1.

Of or pertaining to the river Styx; hence, hellish; infernal. See Styx. At that so sudden blaze, the Stygian throng Bent their aspect. - Milton.

Adj.	1.	Stygian - hellish; "Hence loathed Melancholy.../In Stygian cave forlorn"- Milton
	2.	Stygian - dark and dismal as of the rivers Acheron and Styx in Hades; "in the depths of an Acheronian forest"; "upon those roseate lips a Stygian hue"-Wordsworth Synonyms: Acheronian, Acherontic

Acheronian, Acherontic, Cimmerian, Lethean, Plutonian, Plutonic, Tartarean, chthonian, chthonic, clouded, cloudy, dark and gloomy, devilish, funereal, gloomful, glooming, gloomy, hellborn, hellish, ill-lighted, ill-lit, infernal, lowering, overcast, pandemoniac, pandemonic, purgatorial, somber, sombrous, stormy, sulfurous