An Etymological Dictionary of the German Language/üben
üben, vb., ‘to practise, exercise,’ from MidHG. üeben, OHG. uoben (from *ôbjan), wk. vb., ‘to set agoing, execute, venerate,’ corresponding to OSax. ôƀian, ‘to celebrate,’ Du. oefenen, ‘to exercise, look after,’ Ofc. œ́fa, ‘to practise.’ Allied to OHG. uoba, ‘celebration,’ uobo, ‘tiller of the soil.’ The Teut. root ôb, ‘to execute,’ contained in these cognates, seems to have been originally used of tilling the ground and of religious acts. To this corresponds, according to the permutation of consonants, the Aryan root ō̆p, with which are allied Sans. ā̆pas, n., ‘work’ (espec. religions work), and Lat. ŏpus, n., ‘work’ (connected with ŏperari, espec., ‘to sacrifice’).