School to throw out drunkard (3)
I believe the answer is:
sot
'drunkard' is the definition.
(sot can mean a drunken person)
'school to throw' is the wordplay.
'school' becomes 'S'.
'throw' indicates an anagram.
'to' with letters rearranged gives 'ot'.
's'+'ot'='SOT'
'out' is the link.
(Other definitions for sot that I've seen before include "One's often intoxicated" , "Habitual drinker" , "Boozer" , "Toper" , "Lush" .)