An Etymological Dictionary of the German Language/Schmerz
Schmerz, m., ‘pain,’ from the equiv. MidHG. smërz, m., OHG. smërzo, m., smërza, f.; allied to OHG. smërzan, vb., MidHG. smërzen, ‘to smart, pain,’ AS. smeortan, ‘to pain, smart,’ E. smart, vb. and subst. MidE. smerte, E. smart, adj., make it probable that the cognates are related to Lat. mordêre, ‘to bite,’ Gr. σμερδνός, σμερδαλεός, ‘horrible'; the Aryan root smerd, Teut. smert, signifies perhaps ‘to stick, bite.’ Comp. bitter.