The most common and most likely answer to this crossword clue is the 7 plus 8 letter word UNLUCKY THIRTEEN
I've seen this crossword clue in Financial Times
U
N
L
U
C
K
Y
T
H
I
R
T
E
E
N
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.