Permission to depart for holiday (5)
I believe the answer is:
leave
This clue is a triple definition!
'permission' is the first definition.
(leave is permission or authorisation)
'to depart' is the second definition.
(leaving is a kind of departing)
'for' is a link.
'holiday' is the third definition.
(I've seen this before)
(Other definitions for leave that I've seen before include "Quit; permission" , "Don't take - time off" , "Deposit" , "consent" , "Abandon" .)