blank cheque
noun [ C, usually singular ]
UK ukus( US blank check) FINANCE
a very large amount of money given to a person or organization to spend, or permission to spend a very large amount of money:
The board has not given me a blank cheque, but enough to really become a big player.
blank cheque to do sth Banks do not want to give children the impression that they have a blank cheque to spend as much as they please.
BANKING
a cheque that someone has signed but does not have an amount of money written on it:
It is not a good idea to send blank cheques in the mail.