Spirit of good party-giver (5)
I believe the answer is:
ghost
'spirit' is the definition.
(spirit can mean a ghost)
'good party-giver' is the wordplay.
'good' becomes 'g' (abbreviation).
'party-giver' becomes 'host' (I've seen this in another clue).
'g'+'host'='GHOST'
'of' acts as a link.
(Other definitions for ghost that I've seen before include "One's dying to" , "Spook, spectre" , "insubstantial presence" , "Apparition; faint trace" , "who has a haunting act?" .)