Toper (3)
I believe the answer is:
sot
'toper' is the definition.
(sot is a kind of toper)
This is the entire clue.
(Other definitions for sot that I've seen before include "Lush" , "A chronic drinker" , "Habitual drinker" , "Habitual drunkard" , "One's often intoxicated" .)