The most common and most likely answer to this crossword clue is the 7 letter word PIERROT
I've seen this crossword clue in The Guardian
P
I
E
R
R
O
T
More clues leading to the result PIERROT
- Stage character to go off behind platform
- Clown potentially the downfall of seaside attraction?
- Beset by depression, make mistake of only half being a clown
- Support rubbish bloke in panto
- Nonsense following support for clown
- Clown making most of mistake breaking mine
- Report written about one performer
- Comic entertainer and where he often performed with balls
- Pantomime character wants mole to perish
- Old clown, I blunder into drugs?
Buddy explains!

The straight part
We know that "Pantomime character" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case pantomime character = pierrot.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 PIERROT mean?
PIERROT noun- Alternative form of Pierrot
- Any of various lycaenid butterflies of the genera Tarucus and Castalia, notable for white contrasting with brown or black on the underwings.
- An 18th-century women's low-cut basque with sleeves.