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]

Moby Thesaurus II by Grady Ward, 1.0:

88 Moby Thesaurus words for "misdemeanor":
   atrocity, badness, breach, crime, crime against humanity,
   criminal tendency, criminality, criminosis, deadly sin, delict,
   delinquency, dereliction, discourtesy, disorder, disorderliness,
   disorderly conduct, disruption, disruptiveness, enormity, error,
   evil, evil courses, evildoing, failure, fault, feloniousness,
   felony, frowned-upon behavior, genocide, guilty act, heavy sin,
   hooliganism, horseplay, illegality, impropriety, indiscretion,
   inexpiable sin, iniquity, injury, injustice, lapse, lawbreaking,
   malefaction, malfeasance, malpractice, malum, malversation,
   minor wrong, misbehavior, misconduct, misdeed, misdoing,
   misfeasance, misprision, misprision of treason, mortal sin,
   naughtiness, nonfeasance, nonsanctioned behavior, offense,
   omission, outrage, peccadillo, peccancy, positive misprision,
   roughhouse, rowdiness, rowdyism, ruffianism, sin,
   sin of commission, sin of omission, sinful act, slip,
   thou scarlet sin, tort, transgression, trespass, trip,
   unutterable sin, vandalism, venial sin, vice, viciousness,
   violation, wrong, wrong conduct, wrongdoing



Bouvier's Law Dictionary, Revised 6th Ed (1856):

MISDEMEANOR, crim. law. This term is used to express every offence inferior
to felony, punishable by indictment, or by particular prescribed
proceedings; in its usual acceptation, it is applied to all those crimes and
offences for which the law has not provided a particular name; this word is
generally used in contradistinction to felony; misdemeanors comprehending
all indictable offences, which do not amount to felony, as perjury, battery,
libels, conspiracies and public nuisances.
     2. Misdemeanors have sometimes been called misprisions. (q.v.) Burn's
Just. tit. Misdemeanor; 4 Bl. Com. 5, n. 2; 2 Bar. & Adolph. 75: 1 Russell,
43; 1 Chitty, Pr. 14; 3 Vern. 347; 2 Hill, S. C. 674; Addis. 21; 3 Pick. 26;
1 Greenl. 226; 2 P. A. Browne, 249; 9 Pick. 1; 1 S. & R. 342; 6 Call. 245; 4
Wend. 229; 2 Stew. & Port. 379. And see 4 Wend. 229, 265; 12 Pick. 496; 3
Mass. 254; 5 Mass. 106. See Offence.



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