Choice of work not holding one back (6)
I believe the answer is:
option
'choice' is the definition.
(I know that choice can be written as option)
'work not holding one back' is the wordplay.
'work' becomes 'op' (operation, work done in an operating theatre).
'holding' indicates putting letters inside.
'one' becomes 'i' (Roman numeral).
'back' says the letters should be written backwards.
'not' enclosing 'i' is 'noit'.
'noit' backwards is 'tion'.
'op'+'tion'='OPTION'
'of' acts as a link.
(Other definitions for option that I've seen before include "Something choosable" , "An act of choosing" , "Altenative choice" , "Thing that may be chosen" , "Preference" .)