What's the noun for abysm? Here's the word you're looking for.
abyss
(frequently figuratively) A bottomless or unfathomed depth, gulf, or chasm; hence, any deep, immeasurable; any void space. [First attested in the late 16th century.]
Anything infinite, immeasurable, or profound. [First attested in the late 16th century.]
Moral depravity; vast intellectual or moral depth.