Perspicacious

Someone+who+is+perspicacious+notices%2C+realizes%2C+and+understands+things+quickly.

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Someone who is perspicacious notices, realizes, and understands things quickly.

By: Angelina Wintonick, Co-Editor in Chief

Having a ready insight into and understanding of things.

Adjective. 

The perspicacious salesman earned a great living because he knew how to read his customers.