Garment a playwright has left behind (5)
I believe the answer is:
shawl
'garment' is the definition.
(shawl is a kind of garment)
'a playwright has left behind' is the wordplay.
'a playwright' becomes 'shaw' (George Bernard Shaw).
'has left behind' becomes 'l' (I can't justify this - if you can you should give a lot more credence to this answer).
'shaw'+'l'='SHAWL'
Can you help me to learn more?
(Other definitions for shawl that I've seen before include "Wrap for a baby" , "Cape" , "Cloth wrapped over one's shoulders" , "Shoulder wrap" , "Cloak, wrap" .)