The most common and most likely answer to this crossword clue is the 13 letter word IMPERTINENTLY
I
M
P
E
R
T
I
N
E
N
T
L
Y
More clues leading to the result IMPERTINENTLY
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.