An Etymological Dictionary of the German Language/Trug
Trug, m., ‘deception, illusion,’ ModHG. only, allied to trügen, older triegen, which is derived from the equiv. MidHG. triegen, OHG. triogan, str. vb., corresponding to OSax. bidriogan, ‘to cheat, deceive.’ To these are allied Teut. draumo-, ‘phantom’ (see Traum), as well as OIc. draugr, ‘ghost,’ OSax. gidrog, MidHG. getroc (g), ‘ghost’ (comp. also Zwerg). The Teut. root drū̆g (dwerg), ‘to deceive,’ contained in these words, is based on an Aryan root dhrū̆gh (dhwergh), ‘to overreach, injure’; comp. Sans. druh, ‘to injure (by deceit, craftiness, or enchantment),’ OPers. drauga, ‘lie,’ Zend draoga, ‘lying’ (druj, ‘ghost’).