The most common and most likely answer to this crossword clue is the 7 letter word STARTLE
I've seen this crossword clue in The Guardian
S
T
A
R
T
L
E
More clues leading to the result STARTLE
- Surprise the Parisian after dawn
- Begin extremely late causing alarm
- Surprise the French after kick-off
- Frighten in heartless manner with cunning intervention
- Roget’s gutted to be found in stereotypical shock . . . .
- Latter’s shocked and upset
- Surprise rattles Dicky
- Rising golfer absorbs sharp shock
- Leading light let off alarm …
- Surprise final scene ends after dawn
Buddy explains!

The straight part
We know that "shock" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case shock = startle.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 STARTLE mean?
STARTLE noun- A sudden motion or shock caused by an unexpected alarm, surprise, or apprehension of danger.
- To move suddenly, or be excited, on feeling alarm; to start.
- To excite by sudden alarm, surprise, or apprehension; to frighten suddenly and not seriously; to alarm; to surprise.
- To deter; to cause to deviate.