Startles (9)
(Other definitions for surprises that I've seen before include "Takes unawares" , "Sudden, unexpected events" , "bowls over" , "unexpected things of life" , "Astonishes" .)
'startles' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for alarms that I've seen before include "Flaps" , "Frightens or alerts" , "Causes fear" , "Scares with warning devices" , "Danger signals" .)