An Etymological Dictionary of the German Language/Annotated/prüfen
prüfen, verb, ‘to try, examine, prove, test,’ from Middle High German prüeven, brüeven (preterite pruofte), weak verb, ‘to demonstrate, consider, count, test, put right’; this verb, which is of frequent occurrence from the 12th century, is based on Old French prover (Modern French prouver), which is again derived, like Italian provare, from Latin prŏbâre. The abnormal üe of the Middle High German verb comes from East French üe (East French prüeve, from Latin prŏbat). Compare French prouver, éprouve, English proof (even in Anglo-Saxon prôfian, ‘to demonstrate’). With regard to the treatment of Latin ŏ in recent loan-words see further Schule.