The most common and most likely answer to this crossword clue is the 2 plus 3 plus 4 plus 4 letter word TO SIR WITH LOVE
I've seen this crossword clue in The Daily Telegraph
T
O
S
I
R
W
I
T
H
L
O
V
E
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.