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' says the answer is hidden in the clue.
'OFF' is hidden in the letters of 'coffee'.
(Other definitions for off that I've seen before include "On holiday" , "Discontinued" , "Rancid or not in operation" , "Turned, sour" , "start to race" .)