An Etymological Dictionary of the German Language/Annotated/toll
toll, adjective, ‘mad, frantic, absurd,’ from Middle High German and Old High German tol (with one l), adjective, ‘foolish, absurd,’ to which Old High German tulisc, ‘foolish,’ is allied. Compare Old Saxon, Dutch, and Anglo-Saxon dol, ‘foolish,’ English dull. The Teutonic root dul contained in these words has a variant dwal, which has been preserved in Gothic dwals, foolish, Anglo-Saxon gedwëlan, ‘to err,’ Old High German gitwola, ‘infatuation, delusion, heresy,’ Old Saxon dwalm, ‘infatuation, delusion.’ An Aryan root dhwel, dhul, ‘to be infatuated, deluded,’ is also attested by Sanscrit dhvṛ, dhûr (dhru), ‘to deceive, cheat, injure.’