The most common and most likely answer to this crossword clue is the 9 letter word COMPILING
C
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M
P
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Buddy explains!
The straight part
We know that "Arranging" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case arranging = compiling.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 COMPILING mean?
COMPILING verb- To put together; to assemble; to make by gathering things from various sources.
- To construct, build.
- To use a compiler to process source code and produce executable code.
- To be successfully processed by a compiler into executable code.
- To contain or comprise.
- To write; to compose.