Go off and abandon (5)
I believe the answer is:
leave
I believe this is a double definition.
'go off' is the first definition.
(I've seen this in another clue)
'abandon' is the second definition.
(to abandon something is to leave it behind)
'and' acts as a link.
(Other definitions for leave that I've seen before include "Deposit" , "Pull out" , "Permission (to take holidays?)" , "ditch" , "Time off, depart" .)