καταχθόνιος G2709
katachthónios · kat-akh-thon'-ee-os · Adjective
from κατά and (the ground); subterranean, i.e. infernal (belonging to the world of departed spirits):--under the earth.
1 Occurrence in the King James Bible
Philippians 2:10That at the name of Jesus every knee should bow, of things in heaven, and things in earth, and things under the earth;