Delightful meal reduced by one penny (5)
I believe the answer is:
super
'delightful' is the definition.
(I've seen this before)
'meal reduced by one penny' is the wordplay.
'meal' becomes 'supper' (supper is a kind of meal).
'reduced by' indicates named letters should be taken away.
'one penny' becomes 'p' (short for pence).
'supper' with 'p' taken away is 'SUPER'.
(Other definitions for super that I've seen before include "Terrific, ace" , "Smashing, terrific" , "Gushily great, excellent" , "Exceptionally good" , "(Of product) of extra fine quality" .)