The most common and most likely answer to this crossword clue is the 9 letter word MADDENING
I've seen this crossword clue in The Guardian
M
A
D
D
E
N
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More clues leading to the result MADDENING
Buddy explains!
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 MADDENING mean?
MADDENING verb- To make angry.
- To make insane; to inflame with passion.
- To become furious.
- Causing frustration or anger.
- Leading to insanity.