An Etymological Dictionary of the German Language/leider

by Friedrich Kluge

leider, interj., ‘alas!’ from the equiv. MidHG. leider, OHG. leidôr; prop. a comparat. of the OTeut. adj. mentioned under Leid. With regard to the possibility of its being allied to OHG. lêwes, lês, ‘alas!’ comp. leiden.