The most common and most likely answer to this crossword clue is the 1 plus 3 plus 2 plus 3 plus 8 letter word A RAP ON THE KNUCKLES
I've seen this crossword clue in Independent
A
R
A
P
O
N
T
H
E
K
N
U
C
K
L
E
S
Buddy explains!
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.