Steal from the Prado? Not a Goya, certainly (8,3)
I believe the answer is:
abstract art
'not a goya certainly' is the definition.
I can't tell whether this defines the answer.
'steal from the prado?' is the wordplay.
'steal' becomes 'abstract' (abstracting is a kind of stealing).
'from' is a charade indicator (letters next to each other).
'the prado?' becomes 'art' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'abstract'+'art'='ABSTRACT ART'
Can you help me to learn more?
(Another definition for abstract art that I've seen is " Nonrepresentational paintings, sculpture etc".)