abyss

Hell; the bottomless pit; primeval chaos; a confined subterranean ocean.

'You cannot enter here,' said Gandalf, and the huge shadow halted. 'Go back to the abyss prepared for you! Go back! Fall into the nothingness that awaits you and your Master. Go!'

A bottomless or unfathomed depth, gulf, or chasm; hence, any deep, immeasurable; any void space.

Below is the deep abyss of the Lauterbrunnen valley, and at its head a stately semi-circle of mountains, with the pyramidal Lauterbrunnen Breithorn as the centre-piece.

Anything infinite, immeasurable, or profound.

Moral depravity; vast intellectual or moral depth.

They fell into the abyss of drug addiction.

An impending catastrophic happening.