The most common and most likely answer to this crossword clue is the 11 letter word NETHERWORLD
I've seen this crossword clue in The Times
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More clues leading to the result NETHERWORLD
Buddy explains!
The straight part
We know that "abyss" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case abyss = netherworld.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does NETHERWORLD mean?
NETHERWORLD pronoun- The place to which one's spirit descends upon death, conceived as below the surface of the earth.
- The locale of the spirit world or afterlife, whether deemed to be situated below the world of the living or not.
- Specifically, a location of punishment in the afterlife; a hell.
- (by extension) A hidden, shadowy, or sinister subculture, such as that of organized crime.