Pervade + specacaious = perspicacious. Pervade means that the person can penetrate and specacaious means that the person is speculative i.e. he has a good sight. Combining both the situations means that the person has a better understanding and a keen mental perception.
1.Perspicacious mind has gone to the nub of the situation. The man is a genius!
2. The perspicacious lawyer made his case to the judge and ended up winning the case.
3. Many philosophers must be perspicacious to see the questions many people have not thought of.
4. The perspicacious archer had good aim, but not enough strength to ever hit a target.