Definition of "ween"

And when they will fight they will shock them together in a plump; that if there be 20000 men, men shall not ween that there be scant 10000.

1481, Author unknown (pseudonym Sir John Mandeville), The travels of Sir John Mandeville

And ryght as Arthur was on horsbak / ther cam a damoisel from Morgan le fey and broughte vnto syr Arthur a swerd lyke vnto Excalibur / […] / and sayd vnto Arthur Morgan le fey sendeth here your swerd for grete loue / and he thanked her / & wende it had ben so / but she was fals / for the swerd and the scaubard was counterfeet & brutyll and fals(please add an English translation of this quotation)

1485, Sir Thomas Malory, “viij”, in Le Morte Darthur, book IV

Then sayde Peter unto hym: Perissh thou and thy money togedder. For thou wenest that the gyfte of god maye be obteyned with money?

1526, [William Tyndale, transl.], The Newe Testamẽt […] (Tyndale Bible), [Worms, Germany: Peter Schöffer], Acts

Wise men in old time would ween themselves fools; Fools now in new time will ween themselves wise.

1562, John Heywood, The proverbs, epigrams, and miscellanies of John Heywood

… for I ween he will no longer suffer him to abide among the adulterous and wicked Generation of this World.

1677, Thomas Mall, A cloud of witnesses

But neither heat, nor frost, nor thunder,Shall wholly do away, I ween,The marks of that which once hath been.

1816, S[amuel] T[aylor] Coleridge, “(please specify the page)”, in Christabel: Kubla Khan, a Vision: The Pains of Sleep, London: […] John Murray, […], by William Bulmer and Co. […]

And that junior partnership, I ween, Was the only ship that I ever had seen.

1879, W[illiam] S[chwenck] Gilbert, Arthur Sullivan, composer, “When I was a lad”, in H.M.S. Pinafore; […], San Francisco: Bacon & Company, […]

Yet humble second shall be first, I ween

1884, W.S. Gilbert, Princess Ida

Little ween the snug card-players in the cabin of the responsibilities of the sleepless man on the bridge.

1888–1891, Herman Melville, “[Billy Budd, Foretopman.] Chapter XVIII.”, in Billy Budd and Other Stories, London: John Lehmann, published 1951

Klapaucius too, I ween,Will turn the deepest greenTo hear such flawless verse from Trurl’s machine.

1974, Stanisław Lem, translated by Michael Kandel, The Cyberiad