Spirit exists to restrict punishment at school (10)
I believe the answer is:
liveliness
'spirit' is the definition.
(I know that spirit can be written as liveliness)
'exists to restrict punishment at school' is the wordplay.
'exists' becomes 'lives' ('live' can be a synonym of 'exist').
'to restrict' indicates putting letters inside.
'punishment at school' becomes 'lines'.
'lives' placed around 'lines' is 'LIVELINESS'.
(Other definitions for liveliness that I've seen before include "State of energetic activity" , "Energy" .)