Where does “Judenknecht” come from?

Judenknecht (German) comes from German jude, from Middle High German jüde, from Old High German judo, from Latin Iūdaeus, from Ancient Greek Ἰουδαῖος, from Ancient Greek Ἰουδά, from Hebrew יְהוּדָה — Judas; Judah, Judas.

Judenknecht (German): Jew slave; a slur that could be directed at anyone suspect of having pro-Jewish sentiments or of helping Jews, even in the vaguest or most immaterial way