The Collaborative International Dictionary of English v.0.48:

Contumelious \Con`tu*me"li*ous\ (?or ?; 106), a. [L.
   contumeliosus.]
   1. Exhibiting contumely; rudely contemptuous; insolent;
      disdainful.
      [1913 Webster]

            Scoffs, and scorns, and contumelious taunts. --Shak.
      [1913 Webster]

            Curving a contumelious lip.           --Tennyson.
      [1913 Webster]

   2. Shameful; disgraceful. [Obs.] --Dr. H. More. --
      Con`tu*me"li*ous*ly, adv. -- Con`tu*me"li*ous*ness, n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

contumelious
    adj 1: arrogantly insolent

Moby Thesaurus II by Grady Ward, 1.0:

111 Moby Thesaurus words for "contumelious":
   Rabelaisian, abusive, arrogant, atrocious, audacious, back-biting,
   backhand, backhanded, belittling, bitchy, blasphemous, bold,
   brazen, bumptious, calumniatory, calumnious, catty, cavalier,
   censorious, clannish, cliquish, cold, comminatory, contemptuous,
   cool, critical, cursing, damnatory, defamatory, degrading,
   denunciatory, deprecatory, depreciative, depreciatory, derisive,
   derisory, derogative, derogatory, detractory, dirty, disdainful,
   dismissive, disparaging, dysphemistic, epithetic, exclusive,
   excommunicative, excommunicatory, execratory, familiar, forward,
   foul, fulminatory, haughty, hubristic, humiliating, impertinent,
   imprecatory, impudent, insolent, insulting, invective, left-handed,
   libelous, maledictory, minimizing, obscene, obtrusive, offensive,
   opprobrious, outrageous, overpresumptuous, overweening, pejorative,
   presuming, presumptuous, procacious, profane, pushy, railing, raw,
   ribald, ridiculing, risque, saucy, scandalous, scatologic,
   scolding, scornful, scurrile, scurrilous, severe, slanderous,
   slighting, sneering, sniffy, snobbish, snobby, snooty, snotty,
   supercilious, toploftical, toplofty, truculent, unspeakable,
   uppish, uppity, vile, vilifying, vituperative, withering