Result of unacceptable approach (7)
I believe the answer is:
outcome
'result' is the definition.
(something's outcome is its result or consequence)
'unacceptable approach' is the wordplay.
'unacceptable' becomes 'out' (out can mean incorrect or inappropriate).
'approach' becomes 'come' (e.g. as imperative).
'out'+'come'='OUTCOME'
'of' acts as a link.
(Other definitions for outcome that I've seen before include "End result" , "Result or consequence" , "answer" , "Cute moo (anag.)" , "Eventuality" .)