Definitions

1. adjective

relating to or characteristic of the River Styx, its waters, or the dead; gloomy, dismal, or deathly pale

“The stygial mist rolled in, shrouding the city in an eerie gloom.”

2. noun

a person or thing characterized by or associated with the River Styx, its waters, or the dead

“The stygial apparition materialized before her, its presence sending shivers down her spine.”