Leaving during coffee (3)
I believe the answer is:
off
'leaving' is the definition.
(as in 'I'm off')
'during coffee' is the wordplay.
'during' indicates the answer is hidden within the clue.
'OFF' can be found hidden inside 'coffee'.
(Other definitions for off that I've seen before include "On holiday" , "Discontinued" , "Rancid or not in operation" , "Turned, sour" , "start to race" .)