Die off after incident at close of day (8)
I believe the answer is:
eventide
'close of day' is the definition.
(thesaurus)
'die off after incident' is the wordplay.
'off' is an anagram indicator.
'after' is a charade indicator (letters next to each other).
'incident' becomes 'event' (an incident is an event or happening).
'die' is an anagram of 'ide'.
'ide' after 'event' is 'EVENTIDE'.
'at' acts as a link.
(Other definitions for eventide that I've seen before include "latter part of the day" , "End of the day (poetic)" , "some time later?" , "End of the day to the poet" , "late in the day?" .)