The most common and most likely answer to this crossword clue is the 10 letter word INSCRIBING
I've seen this crossword clue in Financial Times
I
N
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C
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Buddy explains!
The straight part
We know that "writing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case writing = inscribing.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 INSCRIBING mean?
INSCRIBING verb- To write or cut (words) onto (something, especially a hard surface, or a book to be given to another person); to engrave.
- To draw a circle, sphere, etc. inside a polygon, polyhedron, etc. and tangent to all its sides.