Perspicacity

Having or showing penetrating thinking skills; clear-sighted. Such an acuteness of perception is perspicacity. (pron. pər-spə-KAY-shəs, pər-spə-KA-sə-tee) Not to be confused with perspicuous. One easy way to keep out of trouble is to think of "perspicUous" as the "U" word, and remember that it means "Understandable" ? in contrast to the "A" word, "perspicAcious," that means "Astute." Both words come directly from Latin adjectives that mean the same thing they do: "perspicuous" from "perspicuus," and "perspicacious" from "perspicax."