wis
/wɪs
/verb (wisses, wissing, wissed) [no object] archaic
Know well: and, you wis, Lord Julian is a hasty man
Origin
Early 16th century: originally in I wis, alteration of the obsolete adverb iwis 'certainly', erroneously interpreted as 'I know' (associated with wist, past tense of wit2).