Discharge at a bad time (4)
I believe the answer is:
emit
'discharge' is the definition.
(emitting is a kind of discharging)
'a bad time' is the wordplay.
'a bad' indicates an anagram.
'time' with letters rearranged gives 'EMIT'.
'at' acts as a link.
(Other definitions for emit that I've seen before include "Issue" , "Come out!" , "Let out" , "Send forth" , "Give out or pour forth" .)