The most common and most likely answer to this crossword clue is the 9 letter word PERDITION
I've seen this crossword clue in Independent
P
E
R
D
I
T
I
O
N
More clues leading to the result PERDITION
- Row’s beginning to interrupt quiet book? Damnation!
- A speech not about ruin
- Everlasting punishment for a princess into rum
- Cast characters with pride into hell
- Reckless ode I print producing ruin
- Punishment for every issue disregarded at first
- According to one published version, Dante ultimately escapes hell
Buddy explains!

The straight part
We know that "ruin" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ruin = perdition.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 PERDITION mean?
PERDITION noun- Eternal damnation.
- Hell.
- Absolute ruin.