The most common and most likely answer to this crossword clue is the 9 letter word UNCLEARED
I've seen this crossword clue in The Daily Telegraph
U
N
C
L
E
A
R
E
D
Buddy explains!
The straight part
We know that "without authorisation" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case without authorisation = uncleared.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 UNCLEARED mean?
UNCLEARED adjective- Not cleared.
- (of a cheque) That has not been through the clearing process, and whose amount of cash has not been transferred between accounts.