a.

1. 无准备的；不期而来的[Z][（+for）]
   The storm caught them unprepared.

   暴风雨突然袭来，他们毫无准备。

   Students from tropical countries are often unprepared for the British climate.

   热带国家的学生往往对英国的气候毫无准备。

adj.

1. not ready or able to deal with something.
2. (of a thing) not made ready for use.