An Etymological Dictionary of the German Language/Fratze
Fratze, f., ‘grimace, distortions, caricature,’ f., ModHG. only, whence Du. fratsen, f. plur., ‘grimaces, distortions,’ is borrowed. The absence of the word in OHG. and MidHG. favours the supposition that it was borrowed, and we are compelled to accept that view, since it is impossible to trace the word to a satisfactory Teut. source; the proposed derivation from AS. frœtwe, f. plur., ‘work of art, ornaments (carvings?),’ is phonetically impossible. The word might be finally derived from Ital. frasche, plur., Fr. frasgues, ‘tricks, hoax.’