Flees bugle call (6,3)
I believe the answer is:
lights out
I believe this is a double definition.
'flees' is the first definition.
(light out can mean to run away suddenly)
'bugle call' is the second definition.
(I've seen this before)
(Other definitions for lights out that I've seen before include "call at night?" , "Departs" , "Suddenly disappears" , "Go to sleep!" , "when it gets dark" .)