Art or love, it is material for an opera (2,9)
I believe the answer is:
il trovatore
'an opera' is the definition.
(I've seen this before)
'art or love it is material' is the wordplay.
'is material' is an anagram indicator (the letters provide the material for a new word).
'art'+'or'+'love'+'it'='artorloveit'
'artorloveit' with letters rearranged gives 'IL TROVATORE'.
'for' acts as a link.
(Other definitions for il trovatore that I've seen before include "Anvil chorus opera" , "Verdi opera" , "work with singers" , "Leonora" .)