The most common and most likely answer to this crossword clue is the 7 letter word SLASHED
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More clues leading to the result SLASHED
Buddy explains!

The straight part
We know that "vandalised" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vandalised = slashed.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 SLASHED mean?
SLASHED verb- To cut or attempt to cut, particularly:
- To strike violently and randomly, particularly:
- To move quickly and violently.
- To crack a whip with a slashing motion.
- To clear land, (particularly forestry) with violent action such as logging or brushfires or through grazing.
- To write slash fiction.
- To piss, to urinate.
- To work in wet conditions.
- Having been slashed, cut or rent.
- Marked with a slash.