School silver may droop (3)
I believe the answer is:
sag
'droop' is the definition.
('sag' can be a synonym of 'droop')
'school silver' is the wordplay.
'school' becomes 's'.
'silver' becomes 'ag' ('Ag' can be a synonym of 'silver').
's'+'ag'='SAG'
'may' is the link.
(Other definitions for sag that I've seen before include "Hang down loosely" , "Droop, flag" , "Cave in" , "Sinking" , "Decline" .)