Very fine evening meal down by a piano (5)
I believe the answer is:
super
'very fine' is the definition.
'evening meal down by a piano' is the wordplay.
'evening meal' becomes 'supper' (I've seen this before).
'down by a' is a deletion indicator (to be down to something is to be missing it).
'piano' becomes 'p'.
'supper' with 'p' taken out is 'SUPER'.
(Other definitions for super that I've seen before include "Outstanding" , "Great; wonderful" , "Delightful" , "Gushily great, excellent" , "Prefix meaning over-excellent!" .)