An Etymological Dictionary of the German Language/Annotated/zergen
zergen, verb, ‘to torment, tease, vex’; Modern High German only. It may be identical with Middle High German zęrn (and zęrgen), Old High German zęrian (see zehren); yet Dutch tergen, Anglo-Saxon tęrgan, ‘to tug, tease, worry’ (English to tarry), point to a Gothic *targian, which with Russian dergati, ‘to tear, tug,’ indicate an Aryan root dṛgh (compare träge).