School to manage, to an extent (5)
I believe the answer is:
scope
'to an extent' is the definition.
(scope is a kind of extent)
'school to manage' is the wordplay.
'school' becomes 'S'.
'to manage' becomes 'cope' (manage can mean to cope or do well).
's'+'cope'='SCOPE'
(Other definitions for scope that I've seen before include "Range, extent" , "Range of action" , "Range; opportunity" , "Capacity" , "Field" .)