Old French artist heading west, not south (4)
I believe the answer is:
aged
'old' is the definition.
(similar in meaning)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for aged that I've seen before include "Grew older" , "Very old, person or wine" , "Time-worn" , "not like a callow youth" , "Antiquated" .)