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' says the letters should be written in reverse.
'pan' backwards 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" .)