Turned over painting of leaf (5)
I believe the answer is:
folio
'leaf' is the definition.
('folio' can be a synonym of 'leaf')
'turned over painting of' is the wordplay.
'turned over' is a reversal indicator.
'painting' becomes 'oil' (oil painting is a kind of painting).
'oil'+'of'='oilof'
'oilof' backwards is 'FOLIO'.
(Other definitions for folio that I've seen before include "Leaf of book - page number" , "Book; wrapper for loose papers" , "Leaf of paper" , "Book made of folded sheets" , "Sheet folded to form two leaves in book - page number" .)