The most common and most likely answer to this crossword clue is the 9 letter word OVERDRESS
I've seen this crossword clue in Financial Times
O
V
E
R
D
R
E
S
S
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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 OVERDRESS mean?
OVERDRESS noun- Any garment worn over another.
- To wear too many clothes for a particular occasion.
- To wear clothing which is too elaborate or formal for a particular occasion.