From Middle High German prüeven (13th c.), originally restricted to Central German. Ultimately from Latin probāre and hence a doublet of proben and probieren. The Middle High German form with umlaut (and also Rückumlaut in the past tense pruofte) suggests a Proto-West Germanic *prōfijan, whence also Dutch proeven, Middle Low German prö̂ven. The late attestation on the other hand speaks in favour of a later borrowing from Old French prouver. In this case the word may have passed through Middle Dutch, which would explain the umlaut as analogical (cf. the lack of long umlaut vowels in western Dutch vs. their presence in eastern dialects).
prüfen (weak, third-person singular present prüft, past tense prüfte, past participle geprüft, auxiliary haben)
| infinitive | prüfen | ||||
|---|---|---|---|---|---|
| present participle | prüfend | ||||
| past participle | geprüft | ||||
| auxiliary | haben | ||||
| indicative | subjunctive | ||||
| singular | plural | singular | plural | ||
| present | ich prüfe | wir prüfen | i | ich prüfe | wir prüfen |
| du prüfst | ihr prüft | du prüfest | ihr prüfet | ||
| er prüft | sie prüfen | er prüfe | sie prüfen | ||
| preterite | ich prüfte | wir prüften | ii | ich prüfte1 | wir prüften1 |
| du prüftest | ihr prüftet | du prüftest1 | ihr prüftet1 | ||
| er prüfte | sie prüften | er prüfte1 | sie prüften1 | ||
| imperative | prüf (du) prüfe (du) |
prüft (ihr) | |||
1Rare except in very formal contexts; alternative in würde normally preferred.