School to avoid backing plan (8)
I believe the answer is:
schedule
'plan' is the definition.
(schedule is a kind of plan)
'school to avoid backing' is the wordplay.
'school' becomes 'sch'.
'to avoid' becomes 'elude' (eluding is a kind of avoiding**).
'backing' shows that the letters should be reversed in order.
'elude' in reverse letter order is 'edule'.
'sch'+'edule'='SCHEDULE'
(Other definitions for schedule that I've seen before include "Agenda" , "Programme or timetable of planned events" , "Plan for an activity" , "Table of events" , "Rota" .)