Alcoholic drink has a kick, to an extent (4)
I believe the answer is:
saki
'alcoholic drink' is the definition.
'has a kick to an extent' is the wordplay.
'to an extent' indicates a hidden word.
'SAKI' can be found hidden inside 'has a kick'.
(Other definitions for saki that I've seen before include "Japanese rice alcohol - British short story writer" , "author chosen by 29" , "Pen name of short story writer, H.H. Munro, d. 1916" , "Pseudonym of author HH Munro" , "Japanese alcoholic drink made from rice" .)