The most common and most likely answer to this crossword clue is the 10 letter word DIAPHANOUS
I've seen this crossword clue in The Daily Telegraph
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More clues leading to the result DIAPHANOUS
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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 DIAPHANOUS mean?
DIAPHANOUS adjective- Transparent or translucent; allowing light to pass through; capable of being seen through.
- Of a fine, almost transparent, texture; gossamer; light and insubstantial.
- Isorefractive, having an identical refractive index.