Crazy teachers’ society (4)
I believe the answer is:
nuts
'crazy' is the definition.
(thesaurus)
'teachers' society' is the wordplay.
'teachers'' becomes 'nut' (I am not sure about this - if you are sure you should believe this answer much more).
'society' becomes 's' (common abbreviation in names of organisations).
'nut'+'s'='NUTS'
(Other definitions for nuts that I've seen before include "Fruit with edible kernel" , "'Here we go gathering . . . . In May'" , "Crazy (sl.)" , "out to lunch" , "Nibbles" .)