An Etymological Dictionary of the German Language/Weise
Weise, f., ‘manner, mode, way,’ from MidHG. wîse, OHG. wîsa, f., ‘method’; corresponding to the equiv. AS. wîse, E. wise, Du. wijze, OSax. wîsa. From this West Teut. word (in OIc. vísa) the equiv. Rom. cognates, Ital. guisa, Fr. guise, are derived. Teut. wîsô-n- seems, like weise, to be derived from the Teut. root wī̆t, ‘to know’; hence Weise, lit. ‘knowledge’?. See Art. — The suffix -weise (e.g., in teilweise) has been developed in ModHG. in connection with MidHG. phrases, such as in rëgenes wîs, ‘like rain.’