The witching hour (8)
I believe the answer is:
midnight
'the witching hour' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for midnight that I've seen before include "12 hours from noon" , "Possible time for feast" , "When the day changes" , "'It came upon the . . . . . . . . clear' (carol)" , "12am" .)