Working or departing (5)
I believe the answer is:
going
I believe this clue is a double definition.
'working' is the first definition.
(working can mean going or activated)
'departing' is the second definition.
('go' can be a synonym of 'depart')
'or' acts as a link.
(Other definitions for going that I've seen before include "Due to leave" , "Progress" , "Departure; current (rate)" , "Surface condition (that may get tough!)" , "fading" .)