是指尚未支付的费用。outstanding，极好的，突出的，未支付的。 charge， 费用，收费。
这是麦克米兰英语词典里的例句。
an amount of money that is outstanding has not yet been paid:
outstanding debt: All your outstanding debts must be settled now.
一下为outstanding的英文解释
an amount of money that is outstanding has not yet been paid