After midnight a party-giver produces the spirit (5)
I believe the answer is:
ghost
'the spirit' is the definition.
(spirit can mean a ghost)
'after midnight a party-giver' is the wordplay.
'after' is a charade indicator (letters next to each other).
'midnight' becomes 'g' (the middle letter in 'night').
'a party-giver' becomes 'host' (I've seen this in another clue).
'g'+'host' is 'GHOST'.
'produces' acts as a link.
(Other definitions for ghost that I've seen before include "Visible manifestation of a dead person" , "Spectre, wraith" , "Supernatural apparition" , "One's dying to" , "Spirit, spectre" .)