The Collaborative International Dictionary of English v.0.48:

Cavalier \Cav`a*lier"\ (k[a^]v`[.a]*l[=e]r"), n. [F. cavalier,
   It. cavaliere, LL. caballarius, fr. L. caballus. See
   Cavalcade, and cf. Chevalier, Caballine.]
   1. A military man serving on horseback; a knight.
      [1913 Webster]

   2. A gay, sprightly, military man; hence, a gallant.
      [1913 Webster]

   3. One of the court party in the time of king Charles I. as
      contrasted with a Roundhead or an adherent of Parliament.
      --Clarendon.
      [1913 Webster]

   4. (Fort.) A work of more than ordinary height, rising from
      the level ground of a bastion, etc., and overlooking
      surrounding parts.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cavalier \Cav`a*lier"\, a.
   offhand; unceremonious; gay; easy; frank. Opposed to
   serious.
   [1913 Webster +PJC]

         The plodding, persevering scupulous accuracy of the
         one, and the easy, cavalier, verbal fluency of the
         other, form a complete contrast. --Hazlitt.
   [1913 Webster]

   2. High-spirited. [Obs.] "The people are naturally not
      valiant, and not much cavalier." --Suckling.
      [1913 Webster]

   3. Supercilious; haughty; disdainful; curt; brusque.
      [1913 Webster]

   4. Of or pertaining to the party of King Charles I. "An old
      Cavalier family." --Beaconsfield.
      [1913 Webster]

WordNet (r) 3.0 (2006):

cavalier
    adj 1: given to haughty disregard of others [syn: cavalier,
           high-handed]
    n 1: a gallant or courtly gentleman [syn: cavalier,
         chevalier]
    2: a royalist supporter of Charles I during the English Civil
       War [syn: Cavalier, Royalist]

Moby Thesaurus II by Grady Ward, 1.0:

113 Moby Thesaurus words for "cavalier":
   Bayard, Casanova, Don Juan, Don Quixote, Gawain, Lancelot,
   Lothario, Ritter, Romeo, Sidney, Sir Galahad, abrupt, aggressive,
   amoroso, arrogant, bachelor, banneret, baronet, bearish, beastly,
   beau, bluff, blunt, bodyguard, boyfriend, brash, broncobuster,
   brusque, buckaroo, caballero, cavaliere servente, cavalryman,
   chaperon, chevalier, churlish, circus rider, companion, conductor,
   contemptuous, contumelious, convoy, cowboy, cowgirl, cowpuncher,
   crusty, curt, disdainful, dismissive, duenna, equestrian,
   equestrienne, escort, esquire, fellow, fellow traveler, flame,
   gallant, gaucho, gigolo, gruff, guard, harsh, haughty,
   high-and-mighty, horse soldier, horseback rider, horsebacker,
   horseman, horsewoman, inamorato, insolent, jockey, knight,
   knight bachelor, knight banneret, knight baronet, knight-errant,
   lady-killer, lofty, love-maker, man, mounted policeman, necker,
   old man, overbearing, petter, philanderer, postboy, postilion,
   puncher, rider, rough, roughrider, safe-conduct, seducer, severe,
   sharp, sheik, shepherd, short, snippy, squire, steeplechaser,
   sugar daddy, supercilious, superior, surly, swain, trick rider,
   truculent, usher, vaquero, young man



U.S. Gazetteer Counties (2000):

Cavalier -- U.S. County in North Dakota
   Population (2000):    4831
   Housing Units (2000): 2725
   Land area (2000):     1488.458592 sq. miles (3855.089893 sq. km)
   Water area (2000):    21.678216 sq. miles (56.146319 sq. km)
   Total area (2000):    1510.136808 sq. miles (3911.236212 sq. km)
   Located within:       North Dakota (ND), FIPS 38
   Location:             48.755148 N, 98.463479 W
   Headwords:
    Cavalier
    Cavalier, ND
    Cavalier County
    Cavalier County, ND


U.S. Gazetteer Places (2000):

Cavalier, ND -- U.S. city in North Dakota
   Population (2000):    1537
   Housing Units (2000): 750
   Land area (2000):     0.793037 sq. miles (2.053957 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    0.793037 sq. miles (2.053957 sq. km)
   FIPS code:            12940
   Located within:       North Dakota (ND), FIPS 38
   Location:             48.795416 N, 97.623259 W
   ZIP Codes (1990):
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Cavalier, ND
    Cavalier