The most common and most likely answer to this crossword clue is the 9 letter word HARLEQUIN
I've seen this crossword clue in Financial Times
H
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More clues leading to the result HARLEQUIN
- Sort of duck, fast mover, one of five crossing lake
- Arguably one of 15 playing the clown?
- Player perhaps in a pack, a buffoonish type
- Clown Prince unbounded, one of five
- Pantomime character spotted dog
- Buffoon husband, a disaster around the French queen
- Amusing character: flipping posh kid beginning to look like a horse having its tail pulled
- Buffoon halted motorbike on a 1 in 5
- Charles' equine edges out clown
- Clown Prince’s content: one with four siblings
Buddy explains!

The straight part
We know that "Pantomime character/spotted dog" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case pantomime character/spotted dog = harlequin.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 HARLEQUIN mean?
HARLEQUIN noun- A pantomime fool, typically dressed in checkered colorful clothes.
- A greenish-chartreuse color.
- A harlequin duck.
- Any of various riodinid butterflies of the genera Taxila and Praetaxila.
- To remove or conjure away, as if by a harlequin's trick.
- To make sport by playing ludicrous tricks.
- Brightly colored, especially in a pattern like that of a harlequin clown's clothes.
- Of a greenish-chartreuse color.