Son's superior meal (6)
I believe the answer is:
supper
'meal' is the definition.
(supper is a kind of meal)
'son's superior' is the wordplay.
'superior' becomes 'upper' (I've seen this before).
's'+'upper'='SUPPER'
(Other definitions for supper that I've seen before include "Eats late" , "consumer" , "has one had a few drinks?" , "Evening 2 Down" , "Early evening meal" .)