Drunk hides whiskey in study (4)
I believe the answer is:
swot
'study' is the definition.
(I know that swot is a type of study)
'drunk hides whiskey' is the wordplay.
'drunk' becomes 'sot' (both can mean someone who drinks too much).
'hides' indicates putting letters inside.
'whiskey' becomes 'W' (alpha bravo charlie delta ...).
'sot' enclosing 'w' is 'SWOT'.
'in' is the link.
(Other definitions for swot that I've seen before include "Overly studious pupil" , "Study intensively for an exam" , "Informally, one who studies hard" , "One studying too much" , "Person who studies hard" .)