The most common and most likely answer to this crossword clue is the 10 letter word DEPREDATED
I've seen this crossword clue in The Guardian
D
E
P
R
E
D
A
T
E
D
Buddy explains!

The straight part
We know that "Sacked/Sacked" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sacked/sacked = depredated.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 DEPREDATED mean?
DEPREDATED verb- To ransack or plunder; to prey upon.