Final action in school period — ten punished (9)
I believe the answer is:
interment
'final action' is the definition.
(interring of a corpse)
'in school period ten punished' is the wordplay.
'school period' becomes 'term' (I've seen this before).
'punished' indicates an anagram.
'ten' is an anagram of 'ent'.
'in'+'term'+'ent'='INTERMENT'
(Other definitions for interment that I've seen before include "Procedure governing body" , "Burial" , "planting" .)