Cause to jump (7)
I believe the answer is:
startle
'cause to jump' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for startle that I've seen before include "Cause to jump" , "Shock, alarm" , "Shock (someone)" , "Surprise greatly, alarm" , "Rattles (anag.)" .)