Dashing from school after service (7)
I believe the answer is:
raffish
'dashing' is the definition.
('raffish' can be a synonym of 'dashing')
'school after service' is the wordplay.
'school' becomes 'fish'.
'after' is a charade indicator (letters next to each other).
'service' becomes 'raf'.
'fish' put after 'raf' is 'RAFFISH'.
'from' is the link.
(Other definitions for raffish that I've seen before include "Attractively disreputable" , "bohemian" , "Rakish" , "Devil-may-care" , "Carelessly dressed" .)