Etymology: representing Middle English wēte(n , variant forms wite(n infinitive and plural present indicative and subjunctive, and wite imperative and singular present subjunctive, of wit v.¹ (for the other parts of the verb see wot v., wist v.). From the middle of the 16th cent., if not earlier, the form weet seems to be obsolete in ordinary speech, but down to the second decade of the 17th cent. it was frequent as a literary archaism (chiefly poetic), as attributed in the drama to rustic speakers, and as a variant of wit in the phrases to do or give (a person) to wit, (that is) to wit. The archaistic use in the 16th and early 17th cent. was confined to the infinitive, the plural present, and the present participle; but the poets of the 18th cent. and later, who have used the word in imitation of Spenser, have often treated it as a regular verb, with 1st singular present I weet, and inflections weets, weeted. For the examples of wete before 1550, and of the phrases above-mentioned in which to weet = ‘to wit’, see wit v.¹

Etymology: Echoic. Compare weet-weet int. and tweet int.