Styg'i-an, a.

a. [Lat. Stygius, from Styx, Stygis, Gr. Στὺξ, Στυγός, the Styx, i. e., the Hateful, from στυγεῖν, to hate. See STYX.] Of, or pertaining to, Styx, fabled by the ancients to be a river of hell over which the shades of the dead passed, or the region of the dead; hence, hellish; infernal.

At that so sudden blaze, the Stygian throng Bent their aspect. Milton.