Feast of good plays unseen by audience? (8)

I believe the answer is:
offstage
'unseen by audience?' is the definition.
Although both the answer and definition are singular nouns, I don't understand how one could define the other.
'feast of good plays' is the wordplay.
'good' becomes 'g' (abbreviation).
'plays' indicates an anagram.
'feast'+'of'+'g'='feastofg'
'feastofg' is an anagram of 'OFFSTAGE'.
Can you help me to learn more?
(Other definitions for offstage that I've seen before include "From the wings of a theatre?" , "Not visible to the audience" , "behind the scenes" , "Behind-the-scenes" , "not visible from house" .)
