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 finish' suggests the final letters.
The final letter of 'breakfast' is 't'.
'go'+'t'='GOT'
(Other definitions for got that I've seen before include "Received; understood" , "Caught" , "Obtained" , "Landed" , "Acquired" .)