An Etymological Dictionary of the German Language/ach

by Friedrich Kluge

ach, interj., ‘ah! alas!’ from MidHG. ach, OHG. ah; to this is allied MidHG. and ModHG. Ach, ah, n., ‘woe,’ and its deriv., which first occurs in ModHG., ächzen, orig. sense, ‘to utter Ach’ (formed like ihrzen, dutzen).