The most common and most likely answer to this crossword clue is the 4 plus 2 plus 1 plus 4 plus 4 letter word ONCE IN A LIFE TIME
O
N
C
E
I
N
A
L
I
F
E
T
I
M
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.