The most common and most likely answer to this crossword clue is the 9 letter word BRUTALITY
I've seen this crossword clue in The Daily Telegraph
B
R
U
T
A
L
I
T
Y
Buddy explains!

The straight part
We know that "Savagery" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case savagery = brutality.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.
Crossword Answer definitions
BRUTALITY noun- The state of being brutal.
- A cruel or savage act.
- The use of excessive physical force, often in the form of violence.