The most common and most likely answer to this crossword clue is the 5 letter word CAPER
I've seen this crossword clue in The Guardian
C
A
P
E
R
More clues leading to the result CAPER
- Carbon copier for skip
- One taking off supports around skip
- Crime cases taken by police officer half lost
- Accountant with a job in a bank?
- Thorny shrub that can be cut by a lively person?
- Playfully dance and run below headland
- Credit involves coarse person in illegal scheme
- What Batman puts on Robin’s head in jest
- Cloak right for illicit activity
- In which millions will be stolen from van?
Buddy explains!

The straight part
We know that "jest" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case jest = caper.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 CAPER mean?
CAPER noun- A playful leap or jump.
- A jump while dancing.
- A prank or practical joke.
- (usually in plural) Playful behaviour.
- (figuratively) A crime, especially an elaborate heist, or a narrative about such a crime.
- To leap or jump about in a sprightly or playful manner.
- To jump as part of a dance.
- To engage in playful behaviour.
- A vessel formerly used by the Dutch; privateer.
- The pungent grayish green flower bud of the European and Oriental caper (Capparis spinosa), which is pickled and eaten.
- A plant of the genus Capparis.
- The capercaillie.