ME ewis, iwis(se) ＜ OE ewis (adj.) certain, gewisse (adv.) ← Gmc a-🔗⭐🔉

ME ewis, iwis(se) ＜ OE ewis (adj.) certain, gewisse (adv.) ← Gmc a-, i- 'Y-'＋wissa- (← wissa (p.p.) known ← IE weid-, wid- to see: cf. wit^２): cf. Du gewis / OHG giwis (G gewiss certain, certainly) I・wo /wo ｜ -w/

研究社新英和大辞典 ページ 199212 での【seadj.adv.】単語。