The most common and most likely answer to this crossword clue is the 6 letter word FRIGHT
I've seen this crossword clue in The Daily Telegraph
F
R
I
G
H
T
More clues leading to the result FRIGHT
Buddy explains!

The straight part
We know that "Scare" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case scare = fright.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 FRIGHT mean?
FRIGHT noun- A state of terror excited by the sudden appearance of danger; sudden and violent fear, usually of short duration; a sudden alarm.
- Anything strange, ugly or shocking, producing a feeling of alarm or aversion.
- To frighten.
- Frightened; afraid; affright