Shiver in fear or revulsion (7)
I believe the answer is:
shudder
'shiver in fear or revulsion' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for shudder that I've seen before include "Shake convulsively" , "Shiver in fear or revulsion" , "Shiver with horror" , "Vibration" , "Convulse" .)