Shock or surprise (7)
I believe the answer is:
startle
I believe this clue is a double definition.
'shock' is the first definition.
(startling is a kind of shocking)
'surprise' is the second definition.
(to startle someone is to surprise or shock them)
(Other definitions for startle that I've seen before include "Astonish" , "Take (someone) aback" , "Alarm (someone)" , "Cause shock to" , "Rattles (anag.)" .)