Doctor cures most clients (9)
I believe the answer is:
customers
'clients' is the definition.
('customer' can be a synonym of 'client')
'doctor cures most' is the wordplay.
'doctor' indicates anagramming the letters.
'cures'+'most'='curesmost'
'curesmost' with letters rearranged gives 'CUSTOMERS'.
(Other definitions for customers that I've seen before include "They make purchases" , "They might buy" , "Shop's clients" , "Clientele" , "They pay for goods and services" .)