The most common and most likely answer to this crossword clue is the 16 letter word SELF-OPINIONATED
I've seen this crossword clue in Independent
S
E
L
F
-
O
P
I
N
I
O
N
A
T
E
D
More clues leading to the result SELF-OPINIONATED
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-OPINIONATED mean?
SELF-OPINIONATED adjective- Obstinately adhering to one's own opinion.