Outworn garment finally put on by a painter (7)
I believe the answer is:
topcoat
'finally put on by a painter' is the definition.
I can't tell whether this definition defines the answer.
'outworn garment' is the wordplay.
'outworn' becomes 'top' (I can't justify this - if you can you should give a lot more credence to this answer).
'garment' becomes 'coat' (coating is a kind of garmenting).
'top'+'coat'='TOPCOAT'
Can you help me to learn more?
(Other definitions for topcoat that I've seen before include "clothing" , "Heavy winter outer garment" , "Ulster?" , "It's worn on the outside in winter" , "Final layer of paint" .)