The most common and most likely answer to this crossword clue is the 11 letter word COUNTERMAND
I've seen this crossword clue in The Daily Telegraph
C
O
U
N
T
E
R
M
A
N
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.
What does COUNTERMAND mean?
COUNTERMAND noun- An order to the contrary of a previous one.
- To revoke (a former command); to cancel or rescind by giving an order contrary to one previously given.
- To recall a person or unit with such an order.
- To prohibit.
- To oppose; to revoke the command of.