ywis Meaning, Definition & Usage

Y*wis" adverb
OE. ywis, iwis, AS. gewis certain; akin to D. gewis, G. gewiss, and E. wit to know. See Wit to know, and Y-.
  1. Certainly; most likely; truly; probably. Obs. or Archaic
    "Ywis," quod he, "it is full dear, I say." Chaucer.
    She answered me, "I-wisse, all their sport in the park is but a shadow to that pleasure that I find in Plato." Ascham.
    A right good knight, and true of word ywis. Spenser.
    ✍ The common form iwis was often written with the prefix apart from the rest of the word and capitalized, as, I wis, I wisse, etc. The prefix was mistaken for the pronoun, I and wis, wisse, for a form of the verb wit to know. See Wis, and cf. Wit, to know.
    Our ship, I wis, Shall be of another form than this. Longfellow.

Webster 1913