sagacity

noun

Etymology: From French sagacité, from Latin sagācitās (“sagaciousness”), from sagāx (“of quick perception, acute, sagacious”), from sāgiō (“to perceive by the senses”). Equivalent to sagac(ious) + -ity.

1. The quality of being sage, wise, or able to make good decisions; the quality of being perceptive, astute or insightful.

   “Young ladies have great penetration in such matters as these; but I think I may defy even your sagacity, to discover the name of your admirer.”

   “Immediately after the meal, when he was alone again, he set to work to examine Drayton’s papers, of which there lay quite a mass on the table near him and, leaning toward the lamp on his elbow, he weighed the meaning of each with a certain sideward sagacity of gaze, a sagacity that smiled in its self-sureness. Swiss Family Robinson- "....near the mouth of a creek, towards which all our geese and ducks betook themselves; and I, relying on their sagacity, followed in the same course."”

2. Keen sense of smell.

   “[…] this Beast [the Ichneumon] is not only enemy to the Crocodile and Asp, but also to their Egs, which she hunteth out by the sagacity of her nose, and so destroyeth them […]”