The most common and most likely answer to this crossword clue is the 9 letter word CAPARISON
I've seen this crossword clue in The Times
C
A
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More clues leading to the result CAPARISON
- Horse’s trappings a Trojan prince wrapped in fleece?
- Fine covering swindle involving key capital
- Saddle decorator over chasing source of plaster in tin
- Rich clothing around Juliet’s intended, nothing new
- Deception about a Trojan Horse’s cover
- Cheat touring a European city in sumptuous clothing
- About to find Juliet’s suitor against rich clothing and ornaments generally
- Trapping a number cruncher, jailing one
- Dress horse, roughly normal, performs
- Outside a capital city study a type of ornamentation
Buddy explains!

The straight part
We know that "Horse’s trappings" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case horse’s trappings = caparison.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 CAPARISON mean?
CAPARISON noun- The often ornamental coverings for an animal, especially a horse or an elephant.
- Gay or rich clothing.
- To dress up a horse or elephant with ornamental coverings.