The Collaborative International Dictionary of English v.0.48:

Misdemeanor \Mis`de*mean"or\, n.
   1. Ill behavior; evil conduct; fault. --Shak.
      [1913 Webster]

   2. (Law) A crime less than a felony. --Wharton.
      [1913 Webster]

   Note: As a rule, in the old English law, offenses capitally
         punishable were felonies; all other indictable offenses
         were misdemeanors. In common usage, the word crime is
         employed to denote the offenses of a deeper and more
         atrocious dye, while small faults and omissions of less
         consequence are comprised under the gentler name of
         misdemeanors. --Blackstone.
         The distinction, however, between felonies and
         misdemeanors is purely arbitrary, and is in most
         jurisdictions either abrogated or so far reduced as to
         be without practical value. Cf. Felony. --Wharton.
         [1913 Webster]

   Syn: Misdeed; misconduct; misbehavior; fault; trespass;
        transgression.
        [1913 Webster]

WordNet (r) 3.0 (2006):

misdemeanor
    n 1: a crime less serious than a felony [syn: misdemeanor,
         misdemeanour, infraction, violation, infringement]

The Devil's Dictionary (1881-1906):

MISDEMEANOR, n.  An infraction of the law having less dignity than a
felony and constituting no claim to admittance into the best criminal
society.

    By misdemeanors he essays to climb
    Into the aristocracy of crime.
    O, woe was him! -- with manner chill and grand
    "Captains of industry" refused his hand,
    "Kings of finance" denied him recognition
    And "railway magnates" jeered his low condition.
    He robbed a bank to make himself respected.
    They still rebuffed him, for he was detected.
                                                          S.V. Hanipur