An Etymological Dictionary of the German Language/Ketzer

by Friedrich Kluge

Ketzer, m., ‘heretic,’ from MidHG. ketzer, m., ‘heretic,’ also ‘reprobate, Sodomite’ (not recorded in OHG.). The tz presents no difficulties in deriving the word from Gr. καθαρός (καθαροί, a Manichean sect spread throughout the West in the 11th and 12th cents., and persecuted by the Church), if it be assumed that Du. ketter, ‘heretic,’ is a phonetic version of the HG. word. It is true that HG. tz from Gr. θ (Lat. th) cannot be demonstrated; the hard fricative th (þ, θ) may, however, be regarded phonetically as tz, since, e.g., King Chilperic's sign for the was none other than z; the þ in OIc. words sounded also to the Germans of the 9th cent. like z; þór seemed to them zor. So too in Italy the καθαροί were called Gazari.