The Surprising Root of Sagacious

You might expect the root of sagacious to be sage, which, as an adjective, means "wise" or, as a noun, "a wise person." Despite similarities of spelling, sound, and sense, the two words are not closely related. Sagacious comes from sagire, a Latin verb meaning "to perceive keenly." Etymologists believe that sage comes from a different Latin verb, sapere, which means "to taste," "to have good taste," or "to be wise."

Hidden Meaning of Sagacious

Sagacious entered the English language around the beginning of the 17th century and, for some decades, referred to perceptiveness of sight, taste, and especially, smell. One of the first authors to use the word, Edward Topsell, wrote in 1607 of bees searching for something with “a most sagacious smelling-sence.” Sagacious has largely lost the sense (no pun intended) of being keen in sensory perception, and now almost exclusively means "of keen judgment, discerning.” The upshot is that English has words for the state of possessing acute vision (such as far-sighted) and a fine sense of touch (such as sensitive), but lacks any adjectives describing an excellent sense of smell.