Suck up whiskey in cooler (4)
I believe the answer is:
fawn
'suck up' is the definition.
(I know that suck up can be written as fawn)
'whiskey in cooler' is the wordplay.
'whiskey' becomes 'W' (phonetic alphabet: alpha, bravo, charlie etc.).
'in' indicates putting letters inside.
'cooler' becomes 'fan' (something which cools).
'w' put into 'fan' is 'FAWN'.
(Other definitions for fawn that I've seen before include "Bear does, maybe" , "Be servile" , "Pale brown" , "Ingratiate oneself" , "Young fallow deer" .)