chthonian
\ THOH-nee-uhn \ , adjective;
1. Classical Mythology . of or pertaining to the deities, spirits, and other beings dwelling under the earth.
Quotes:
Perhaps the smell of blood, dark and chthonian , at the precise moment that the bird screamed, awakened something deep and intrinsic in what remained of Pan's consciousness.
-- Tom Robbins, "Jitterbug Perfume , " 1984
Meanwhile, the obstinate insistence of the chthonian voices did not let up, as if the threatening presence of enemies, of the powerful who persecuted the people of the Lord, remained unresolved.
-- Umberto Eco, Translated by Richard Dixon, "The Name of the Rose ," 2014
Origin:
Chthonian entered English in the 1840s from the Greek word chthṓn meaning "earth."
Dictionary.com
