wis
Wis (adv) means Definitely, or without any doubt.
Etymology
Inherited from Middle English wis (“certain, sure”), from an aphetic form of Middle English iwis, ywis (“certain, sure”) (from Old English ġewiss (“certain, sure”)), or of North Germanic origin, cognate with Icelandic viss (“certain, sure”), Dutch gewis (“certain, sure”), and German gewiss (“certain, sure”). Ultimately from Proto-Germanic *gawissaz. More at iwis.