An Etymological Dictionary of the German Language/prüfen
prüfen, vb., ‘to try, examine, prove, test,’ from MidHG. prüeven, brüeven (pret. pruofte), wk. vb., ‘to demonstrate, consider, count, test, put right’; this vb., which is of frequent occurrence from the 12th cent., is based on OFr. prover (ModFr. prouver), which is again derived, like Ital. provare, from Lat. prŏbâre. The abnormal üe of the MidHG. vb. comes from East Fr. üe (East Fr. prüeve, from Lat. prŏbat). Comp. Fr. prouver, éprouve, E. proof (even in AS. prôfian, ‘to demonstrate’). With regard to the treatment of Lat. ŏ in recent loan-words see further Schule.