The most common and most likely answer to this crossword clue is the 2 plus 4 plus 1 plus 11 letter word TO KILL A MOCKINGBIRD
T
O
K
I
L
L
A
M
O
C
K
I
N
G
B
I
R
D
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.