Old French artist practically flipped (4)
'old' is the definition.
('aged' can be similar in meaning to 'old')
'french artist practically flipped' is the wordplay.
'french artist' becomes 'degas' (I've seen this before).
'practically' means to remove the last letter.
'flipped' is a reversal indicator.
'degas' with its final letter taken away is 'dega'.
'dega' back-to-front is 'AGED'.
(Other definitions for aged that I've seen before include "Geriatric", "Very old, person or wine", "Matured like wine in wood", "Time-worn", "Like Uncle Arly".)