Society to encourage operator (7)
I believe the answer is:
surgeon
'operator' is the definition.
(thesaurus)
'society to encourage' is the wordplay.
'society' becomes 's' (common abbreviation in names of organisations).
'to encourage' becomes 'urgeon' (urging on is a kind of encouraging).
's'+'urgeon'='SURGEON'
(Other definitions for surgeon that I've seen before include "Medical practitioner - go nurse (anag)" , "one used to working in the theatre" , "Performer of operations" , "9 practitioner (through keyhole?)" , "Theatre operator" .)