Support amateur opera (4)
I believe the answer is:
aida
'opera' is the definition.
(Aida is an example)
'support amateur' is the wordplay.
'support' becomes 'aid' ('aid' can be a synonym of 'support').
'amateur' becomes 'a'.
'aid'+'a'='AIDA'
(Other definitions for aida that I've seen before include "Egyptian opera by 11 Down" , "work of grand proportions" , "Princess" , "eponymous heroine" , "title role" .)