Carte blanche (4,4)
I believe the answer is:
free rein
'carte blanche' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for free rein that I've seen before include "Give it to remove all constraints" , "Unlimited scope for action" , "Liberty over actions" , "'The removal of constraints (4,4)'" , "Carte blanche" .)