Doctor gets points for costume (5)
I believe the answer is:
dress
'costume' is the definition.
(I know that costume can be written as dress)
'doctor gets points for' is the wordplay.
'doctor' becomes 'Dr' (abbreviation).
'gets' is a charade indicator (letters next to each other).
'points for' becomes 'ess' (I can't justify this - if you can you should give a lot more credence to this answer).
'dr'+'ess'='DRESS'
Can you help me to learn more?
(Other definitions for dress that I've seen before include "get into gear" , "changing gear" , "Cultivate < tidy" , "Shift" , "formal wear" .)