Recoil, finding head of caterpillar in drink (5)
I believe the answer is:
wince
'recoil' is the definition.
(to wince is to recoil or flinch)
'head of caterpillar in drink' is the wordplay.
'head of' says to take the initial letters.
'in' is an insertion indicator.
'drink' becomes 'wine' (wine is an alcoholic drink).
The initial letter of 'caterpillar' is 'c'.
'c' going inside 'wine' is 'WINCE'.
'finding' acts as a link.
(Other definitions for wince that I've seen before include "Visibly react to pain" , "Start back in pain" , "Make face showing pain" , "Cringe" , "Involuntary grimace of pain" .)