Come before the school principal (4)
I believe the answer is:
head
I believe this clue is a double definition.
'come before' is the first definition.
(thesaurus)
'the school principal' is the second definition.
('head' can be a synonym of 'school principal')
(Other definitions for head that I've seen before include "See 25" , "See 12" , "School boss" , "Chief; bonce" , "Skull" .)