noun
perspicacity
per-spih-KAS-uh-tee/ˌpɜːrspɪˈkæsəti/
The ability to understand things clearly and judge them accurately.
Her perspicacity helps her recognize problems before the rest of us.

Etymology
Perspicacity turns the sharp-sighted quality of perspicax into a noun. Physical keenness of sight supplies the image for clear understanding: the ability to see into a matter and discern it accurately.
In context
That eye, with unfathomable perspicacity, seemed to pry into her empty pockets and pierce her penniless state.
More examples
- His perspicacity makes him a trusted adviser on difficult decisions.
- The review shows remarkable perspicacity about the novel’s characters.
- With her usual perspicacity, Maya identifies the real reason negotiations fail.
Forms
perspicacious adjective — Quick to understand and judge accurately.