The most common and most likely answer to this crossword clue is the 4 letter word PUNS
P
U
N
S
Buddy explains!

The straight part
We know that "jokes" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case jokes = puns.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 PUNS mean?
PUNS noun- A Korean unit of length equivalent to about 0.3 cm.
- A joke or type of wordplay in which similar definitions or sounds of two words or phrases, or different definitions of the same word, are deliberately confused.
- To beat; strike with force; to ram; to pound, as in a mortar; reduce to powder, to pulverize.
- To make or tell a pun; to make a play on words.