(a.) Being or lying under the surface of the earth; situated within the earth, or under ground; as, subterranean springs; a subterraneous passage.

abstruse beclouded blind close clouded concealed covered covert deep-buried drowned eclipsed engulfed flooded guarded hid hidden immersed in a cloud in a fog in eclipse in purdah in the wings incommunicado inundated latent mysterious obfuscated obscure obscured occult privy recondite secluded secluse secret sequestered shrouded subaqueous submarine submerged submersed subterranean subterraneous sunken under an eclipse under cover under house arrest under wraps underground undersea underwater unknown wrapped in clouds