You are overdrawn on your account if you withdraw more money from the account than it currently holds. If you are overdrawn then you will most likely incur some charge relating to the amount you are overdrawn, unless you are overdrawn by prior arrangement.

The withdrawal of more money than an account actually has on deposit.

When more than the existing balance is withdrawn from an account.

When an amount of money is taken out of a bank account which is greater than the balance of the account. Fees will usually be charged for overdrawn accounts and dishonoured cheques.

When more money is withdrawn from a bank account than it contains.