Cold response (6)
I believe the answer is:
shiver
'cold response' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for shiver that I've seen before include "Momentary tremble" , "Shake (with cold, excitement etc)" , "Shake uncontrollably" , "Tremble convulsively" , "Tremble from cold or with fear" .)