The most common and most likely answer to this crossword clue is the 9 letter word VERDIGRIS
I've seen this crossword clue in The Times
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More clues leading to the result VERDIGRIS
- Blue-green coat is mine — river’s damaged outside
- Composer firmly holds piano should go – it may affect the brass
- Coat of metal obtained from excavation in meandering rivers
- Composer meeting King George is appearing in green
- Discover dig risks exposing oxidation
- Singer regularly appears in composer’s green coat?
- Italian composer linked to Spanish painter's green pigment
Buddy explains!
The straight part
We know that "Blue-green coat" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case blue-green coat = verdigris.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 VERDIGRIS mean?
VERDIGRIS noun- A blue-green patina or rust that forms on copper-containing metals.
- Copper acetate.
- The colour of this patina or material.
- To cover, or coat, with verdigris.