An Etymological Dictionary of the German Language/Annotated/Ohrfeige

Ohrfeige, feminine, ‘box on the ear,’ first occurs in early Modern High German, similar to Dutch oorvijg; usually regarded as a facetious corruption of Dutch oorveeg, ‘box on the ear,’ in which veeg (cognate with Modern High German fegen) signifies ‘stroke, cut.’ It may, like Dachtel, Kopfnüsse, Maulschelle (properly a kind of pastry), be a euphemistic expression.