The most common and most likely answer to this crossword clue is the 8 letter word SAVAGERY
I've seen this crossword clue in The Guardian
S
A
V
A
G
E
R
Y
More clues leading to the result SAVAGERY
- Rescue curtailed: a European country losing man in barbarous attack?
- It recalled silver in highly uncivilised state
- Vandalise grave in utter viciousness
- Very bad rage, beset by utter brutality
- Vandalised grave standing in for one show of uncivilised behaviour
- Grave wrecked in utter barbarity
- Hiding silver in stash, trains for uncivilised behaviour
Buddy explains!

The straight part
We know that "viciousness" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case viciousness = savagery.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 SAVAGERY mean?
SAVAGERY noun- Savage or brutal behaviour; barbarity.
- A violent act of cruelty.
- Savages collectively; the world of savages.
- Wild growth of plants.