The most common and most likely answer to this crossword clue is the 9 letter word CARBONISE
I've seen this crossword clue in Financial Times
C
A
R
B
O
N
I
S
E
More clues leading to the result CARBONISE
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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 CARBONISE mean?
CARBONISE verb- To turn something to carbon, especially by heating it; to scorch or blacken.
- To react something with carbon.