Just a whit on wit
“Witty” comes from the Old English wittig “'clever, wise, sagagious; in one's right mind,'” according to the Online Etymology Dictionary.
It's the adjective form of wit, which, according to the same dictionary, goes back to the Old English word witan “to know.”
Since “brevity is the soul of wit,” as Shakespeare wisely noted, here's just one more point to ponder by another keen societal observer:
"Words may show a man's wit but actions his meaning."
Painting of Franklin by Benjamin Wilson, 1759
Photo courtesy of Wikipedia