sapient

sapient \SAY-pee-uhnt\, adjective:

Wise; sage; discerning.

By actual measurement they are the brainiest of birds, and on subjective evidence they seem more sapient than most other living creatures.
-- David Quammen, "Bird Brains", New York Times, August 1, 1999

He also gives much of the book over to the voice and point of view of Wyatt's bright, quirky Aunt Ellen, who functions as a sapient observer of the world of the novel.
-- Lorrie Moore, "God Does Not Love Aunt Ellen", New York Times, February 14, 1993

That he has on his side Lord Jenkins and Lady Williams . . . , that Ming Campbell is backing him, that the trusty and sapient counsellor of previous leaders, Lord Holme, is discreetly installed at his side, might seem to dispose of the notion that Kennedy is not a serious man.
-- "It isn't a one horse race", The Guardian, July 20, 1999

Sapient comes from Latin sapiens, sapient-, present participle of sapere, "to taste, to have sense, to know."