subterranean

As adjectives the difference between secretive and subterranean

is that secretive is having an inclination to secrecy while subterranean is below ground, under the earth, underground.

As adjectives the difference between subterranean and subsurface

is that subterranean is below ground, under the earth, underground while subsurface is below the surface.

As a noun subsurface is

something that is below the layer that is on the surface.

As adjectives the difference between extraterrestrial and subterranean

is that extraterrestrial is originating from outside of the earth's atmosphere, from space, or from another planet; alien to earth or its environment while subterranean is below ground, under the earth, underground.

As a noun extraterrestrial

is a being originating from outside of the earth's atmosphere, from space, or from another planet; an alien.

As adjectives the difference between subterranean and subterrestrial

is that subterranean is below ground, under the earth, underground while subterrestrial is under the earth; subterranean.

As adjectives the difference between epigeal and subterranean

is that epigeal is (biology) living near the surface of the ground while subterranean is below ground, under the earth, underground.

As adjectives the difference between subterranean and spiritual

is that subterranean is below ground, under the earth, underground while spiritual is of or pertaining to the spirit or the soul.

As a noun spiritual is

a Christian religious song, especially one in an African-American style, or a similar non-religious song.

As adjectives the difference between subterraneal and subterranean

is that subterraneal is obsolete form of lang=en while subterranean is below ground, under the earth, underground.

As a noun taxonomy

is the science or the technique used to make a classification.

As an adjective subterranean is

below ground, under the earth, underground.

Superterranean is a antonym of subterranean.

As adjectives the difference between subterranean and superterranean

is that subterranean is below ground, under the earth, underground while superterranean is aboveground.

As an adjective subterranean

is below ground, under the earth, underground.

As a noun aflaj is

an irrigation system which catches mountain water and controls its movement down man-made subterranean channels, found in Oman.