Strong's G2709 — καταχθόνιος (adjective)
katachthonios (kat-akh-thon'-ee-os) adj.
1. subterranean, i.e. infernal (belonging to the world of departed spirits)
[from G2596 and chthon (the ground)]
KJV: under the earth 
Root(s): G2596 
Hebrew root: κατά
Occurrences: 1