Etymology Dictionary

YWIS,  certainly.  (E.)   In Spenser, F. Q. ii. 1. 19.   M.E. ywis, Chaucer, C. T. 3277; iwis, Ancren Riwle, p. 270, l. 11.—A.S. gewis, adj., certain, gewislíce, adv., certainly, Grein, i. 483.   The adj. came to be used adverbially. + Du. gewis, adj. and adv., certain, certainly. + Icel. viss, certain. + Dan. vis, certain; vist, certainly. + Swed. viss, certain; visst, certainly. + G. gewiss, certainly.   β. The ge- is a mere prefix; see Y-.   The adj. is from the Teut. type WISA, certain, Fick, iii. 306.   Related to Wise and Wit, verb.   Cf. Goth. wissa, I knew.   ¶ It is particularly to be noted that the commonest form in MSS. is iwis, in which the prefix (like most other prefixes) is frequently written apart from the rest of the word, and not unfrequently the i is represented by a capital letter, so that it appears as I wis.   Hence, by an extraordinary error, the I has often been mistaken for the 1st pers. pron., and the verb wis, to know, has been thus created, and is given in many dictionaries!   But it is a pure fiction, and the more remarkable because there actually exists a M.E. causal verb wissien or wissen, but it means to teach, shew, instruct.   The easiest test by which to gauge any one's knowledge of Middle-English is to ask him to explain clearly and to parse the words wit, wot, wistë, wist, I wisse, and i-wis.   If he fails, his opinion is valueless.