all-time

1. ADJ You use all-time when you are comparing all the things of a particular type that there have ever been. For example, if you say that something is the all-time best, you mean that it is the best thing of its type that there has ever been. 空前的[ADJ n]

The president's popularity nationally is at an all-time low. 总统在全国的声望处于历史最低点。