An Etymological Dictionary of the German Language/zanken

by Friedrich Kluge

zanken, vb., ‘to quarrel,’ from late MidHG. zanken, zęnken, ‘to dispute’; a remarkably late word, not recorded in the earlier Teut. periods. Perhaps MidHG. zanke (a variant of Zinke), ‘prong, point,’ is the base of zanken, which must then have meant ‘to be pointed.’