perspicacity

/ˌpɜrspɪˈkæsəti/
noun
  1. The ability to understand things quickly and accurately; keen judgment and insight.
    • Her perspicacity in reading people made her an excellent negotiator.
    • The journalist's perspicacity allowed her to see through the politician's excuses.
    • With great perspicacity, the chess player predicted his opponent's next five moves.