"mental capacity," Old English wit, more commonly gewit, from Proto-Germanic *witjan (cf. Old Saxon wit, Old Norse vit, Danish vid, Swedish vett, Old Frisian wit, Old High German wizzi "knowledge, understanding, intelligence, mind," German Witz "wit, witticism, joke," Gothic unwiti "ignorance"), from PIE *woid-/*weid-/*wid- "to see," metaphorically "to know" (see vision). Related to Old English witan "to know" (source of wit (v.)). Meaning "ability to make clever remarks in an amusing way" is first recorded 1540s; that of "person of wit or learning" is from late 15c. For nuances of usage, see humor.
A witty saying proves nothing. [Voltaire, Diner du Comte de Boulainvilliers]
Wit ought to be five or six degrees above the ideas that form the intelligence of an audience. [Stendhal, "Life of Henry Brulard"]
"know," Old English witan "to know," from Proto-Germanic *witanan "to have seen," hence "to know" (cf. Old Saxon witan, Old Norse vita, Old Frisian wita, Middle Dutch, Dutch weten, Old High German wizzan, German wissen, Gothic witan "to know"); see wit (n.). The phrase to wit, almost the only surviving use of the verb, is first recorded 1570s, from earlier that is to wit (mid-14c.), probably a loan-translation of Anglo-French cestasavoir, used to render Latin videlicet (see viz.).