If you have an overdraft, you have spent more money than you have in your bank account, and so you are in debt to the bank.
例句
When I left Cambridge I had a ￡10,000 overdraft...我離開劍橋時，透支了1萬英鎊。Her bank warned that unless she repaid the overdraft she could face legal action.銀行警告她如果不償還透支錢款，她將面臨訴訟。
英漢詞典釋義
n.
透支, 透支額
An overdraft resulted when a 1000 cheque was drawn against only 900 in the account.當賬戶上只有900美元時你支取1000美元, 那就造成了透支。