Greek god comes back for forty winks (3)
I believe the answer is:
nap
'forty winks' is the definition.
(synonyms)
'greek god comes back' is the wordplay.
'greek god' becomes 'Pan' (Pan is an example).
'comes back' is a reversal indicator.
'pan' back-to-front is 'NAP'.
'for' is the link.
(Other definitions for nap that I've seen before include "A daytime doze" , "A brief sleep, forty winks" , "Snatch forty winks" , "Sleep briefly" , "Take forty winks" .)