What makes perfect doctors? (8)
I believe the answer is:
practice
'what makes perfect' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for practice that I've seen before include "It makes perfect, they say" , "Doctor's premises" , "attempt at perfection" , "It makes perfect, 'tis said" , "Custom" .)