alackaday

from The Collaborative International Dictionary of English v.0.48

Alackaday \A*lack"a*day`\, interj. [For alack the day. Cf.
   Lackaday.]
   An exclamation expressing sorrow.
   [1913 Webster]

   Note: Shakespeare has "alack the day" and "alack the heavy
         day." Compare "woe worth the day."
         [1913 Webster]