Doctor one copying rag trader (6)
I believe the answer is:
draper
'trader' is the definition.
(I know that draper is a type of trader)
'doctor one copying rag' is the wordplay.
'doctor' becomes 'Dr' (abbreviation).
'one copying rag' becomes 'aper' (I can't explain this - if you can you should believe this answer much more).
'dr'+'aper'='DRAPER'
Can you help me to learn more?
(Other definitions for draper that I've seen before include "Dealer in fabrics etc" , "One sells clothes" , "Cloth merchant" , "man of the cloth" , "Dealer in fabrics and sewing materials" .)