o·ver·draw (v r-drô) v. o·ver·drew (-dr), o·ver·drawn (-drôn), o·ver·draw·ing, o·ver·draws. v. tr. 1. To draw against (a bank account) in excess of credit.
An overdraft occurs when withdrawals from a bank account exceed the available balance which gives the account a negative balance - a person can be said to be "overdrawn".