iwis
\ih-WIS\, adverb;
1.Obsolete. certainly.
Quotes:
"Ye, iwis," quoth that other wye, "here is wayth fayrest / That I sey this seven yere in sesoun of wynter."
-- Sir Gawain and the Green Knight, circa 1375
There be fools alive, iwis, / Silver'd o'er; and so was this. / Take what wife you will to bed, / I will ever be your head…
-- William Shakespeare, The Merchant of Venice, 1600
Origin:
Iwis has been around in English since before 900. It finds its roots in the Old English adjective gewiss meaning "certain."
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