postdate verb [T] (WRITE DATE) to write a date on a document, such as a cheque or letter, that is later than the date on which you are writing it, usually to get some advantage: Luckily, she let me postdate the...

to write a date on a document, especially a cheque, that is later than the date on which you are writing it: If you cannot trust the salesman to wait until the date on a cheque before presenting it, then post-dating...