1. be caught with chaff : 上当, 受骗;
及物动词
名词
1. 谷糠;麸皮
Chaff is the outer part of grain such as wheat. It is removed before the grain is used as food.
2. 分清良莠;去芜存菁
If you separate the wheat from the chaff or sort the wheat from the chaff, you decide which people or things in a group are good or important and which are not.