Definition
Used to describe someone who is very astute and not easily deceived or tricked.
不容易受骗
Don't try to trick him; there are no flies on him.
别想骗他；他可不是好糊弄的。
She has been in the business for years, and there are no flies on her.
她在这行已经多年，非常精明。
In business negotiations, you have to be alert because there are no flies on the other party.
在商业谈判中，你必须保持警觉，因为对方非常精明。