Difference Between Perspicacious and PerspicuousPerspicacious has the following meanings:-
1. Having or showing penetrating mental discernment; clear-sighted: “The judge was perspicacious enough to find out that the witness had been tutored.”
2. Having or showing an ability to notice and to understand things that are difficult or not obvious: “Perspicacious observations of the critic made the novel all the more popular and its sale touched a new height.”

Perspicuous , on the other hand, means clearly expressed or presented; easy to understand: “The speaker was so perspicuous while delivering the sermon that even ordinary people could understand the mystery of life and death.”