The most common and most likely answer to this crossword clue is the 16 letter word SELF-DEPRECATING
I've seen this crossword clue in Financial Times
S
E
L
F
-
D
E
P
R
E
C
A
T
I
N
G
More clues leading to the result SELF-DEPRECATING
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.
What does SELF-DEPRECATING mean?
SELF-DEPRECATING adjective- Expressing disapproval or being critical of oneself, especially modestly or humorously so.