Obtained leave to finish breakfast (3)
I believe the answer is:
got
'obtained' is the definition.
('get' can be a synonym of 'obtain')
'leave to finish breakfast' is the wordplay.
'leave' becomes 'go' (to go is to depart or leave).
'to finish' suggests the final letters.
The last letter of 'breakfast' is 't'.
'go'+'t'='GOT'
(Other definitions for got that I've seen before include "Received; understood" , "Caught" , "Obtained" , "Landed" , "Acquired" .)