An Etymological Dictionary of the German Language/tasten
tasten, vb., ‘to touch, fumble, grope,’ from the equiv. MidHG. tasten, wk. vb. Borrowed about 1200 A.D. from the Romance cognate Ital. tastare (Fr. tâter), ‘to feel, fumble,’ which is based on a Lat. *taxitare (allied to late Lat. taxare, ‘to touch sharply’).