The Collaborative International Dictionary of English v.0.48:

Misfortune \Mis*for"tune\, n.
   Bad fortune or luck; calamity; an evil accident; disaster;
   mishap; mischance.
   [1913 Webster]

         Consider why the change was wrought,
         You 'll find his misfortune, not his fault. --Addison.
   [1913 Webster]

   Syn: Calamity; mishap; mischance; misadventure; ill; harm;
        disaster. See Calamity.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Misfortune \Mis*for"tune\, v. i.
   To happen unluckily or unfortunately; to miscarry; to fail.
   [Obs.] --Stow.
   [1913 Webster]

WordNet (r) 3.0 (2006):

misfortune
    n 1: unnecessary and unforeseen trouble resulting from an
         unfortunate event [syn: misfortune, bad luck]
    2: an unfortunate state resulting from unfavorable outcomes
       [syn: misfortune, bad luck, tough luck, ill luck]
       [ant: good fortune, good luck, luckiness]

The Devil's Dictionary (1881-1906):

MISFORTUNE, n.  The kind of fortune that never misses.