Old French artist not quite coming round (4)
I believe the answer is:
aged
'old' is the definition.
(similar in meaning)
'french artist not quite coming round' is the wordplay.
'french artist' becomes 'degas' (Edgar Degas, 1834-1917).
'not quite' means to remove the last letter (most but not all of the word).
'coming round' is a reversal indicator.
'degas' with its final letter removed is 'dega'.
'dega' written backwards gives 'AGED'.
(Other definitions for aged that I've seen before include "Antiquated" , "Ripened, matured" , "Very old, person or wine" , "Getting on" , "Got older" .)