Honorary secretary in university departs (6)
I believe the answer is:
unpaid
'honorary' is the definition.
(as in an honorary position)
'secretary in university departs' is the wordplay.
'secretary' becomes 'PA' (abbreviation for personal assistant).
'in' indicates putting letters inside.
'university' becomes 'uni' (short for university).
'departs' becomes 'd' (common abbreviation e.g. train timetables).
'pa' put within 'uni' is 'unpai'.
'unpai'+'d'='UNPAID'
(Other definitions for unpaid that I've seen before include "Without wages" , "Overdue" , "(Of debt) outstanding" , "Outstanding, owing" , "volunteer" .)