Shrink animal with hesitation (5)
I believe the answer is:
cower
'shrink' is the definition.
(I've seen this before)
'animal with hesitation' is the wordplay.
'animal' becomes 'cow' (cow is a kind of animal**).
'with hesitation' becomes 'er' (I've seen this in other clues).
'cow'+'er'='COWER'
(Other definitions for cower that I've seen before include "Cringe, crouch" , "Shrink back in fear" , "Bend in fear" , "Grovel in fear" , "Quail" .)