Complete freedom to act as one wishes (5,7)
I believe the answer is:
carte blanche
'complete freedom to act as one wishes' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for carte blanche that I've seen before include "free rein" , "Full discretionary power" , "total freedom" , "Complete discretion" , "Unrestricted authority" .)