The most common and most likely answer to this crossword clue is the 8 letter word ALTERING
I've seen this crossword clue in The Guardian
A
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More clues leading to the result ALTERING
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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 ALTERING mean?
ALTERING verb- To change the form or structure of.
- To become different.
- To tailor clothes to make them fit.
- To castrate, neuter or spay (a dog or other animal).
- To affect mentally, as by psychotropic drugs or illness.
- Alteration