somebody who can judge and understand things clearly
perspicacious - sharp
If you are ‘perspicacious’, then you are very good at noticing, comprehending, or analyzing somebody or something. It also implies a natural attentiveness and foresight which makes this a highly prized attribute, particularly in a professional environment.
Jane was perspicacious enough to sell her shares just a few days before the market unexpectedly crashed.
I have to admire Alex’s perspicaciousness. He told me not to trust John and he was right. The man turned out to be a con artist.
The boss foresaw the coming demand with her usual perspicacity. That’s why we were so well prepared.