carte blanche /ˌkɑːt ˈblɑːnʃ $ ˌkɑːrt-/ BrE AmE noun [uncountable]
[ Date: 1700-1800 ; Language: French ; Origin: 'white card, document with no writing' ]
permission or freedom to do whatever you want:
The new manager will be given carte blanche as long as she can increase the company’s profits.
She had carte blanche to produce a film suitable for children.