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]

U.S. Gazetteer (1990):

Cavalier, ND (city, FIPS 12940)
  Location: 48.79531 N, 97.62430 W
  Population (1990): 1508 (717 housing units)
  Area: 1.8 sq km (land), 0.0 sq km (water)

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