Christiane Amanpour dropped a serious $10 word on this Sunday's installment of "This Week." So serious was this vocabulary that a graphic defining it was added to the screen.

In a debate about the Constitution, Amanpour said the word "perspicacious," which the graphic helpfully defines as "having keen vision; clear-sighted."

Fast-forward to about 6:20 in the clip below, embedded courtesy ABC, to get your vocabulary lesson.

(h/t: Mediaite)