Affair during night never recalled (5)
I believe the answer is:
event
'affair' is the definition.
(I've seen this in another clue)
'during night never recalled' is the wordplay.
'during' indicates a hidden word.
'recalled' is a reversal indicator.
'tneve' can be found hidden inside 'night never'.
'tneve' written backwards gives 'EVENT'.
(Other definitions for event that I've seen before include "important" , "Incident, occurrence" , "Meeting" , "Something taking place" , "Something going on" .)