The Collaborative International Dictionary of English v.0.48:

Pompous \Pomp"ous\, a. [F. pompeux, L. pomposus. See Pomp.]
   1. Displaying pomp; stately; showy with grandeur;
      magnificent; as, a pompous procession.
      [1913 Webster]

   2. Ostentatious; pretentious; boastful; vainlorious; as,
      pompous manners; a pompous style. "Pompous in high
      presumption." --Chaucer.
      [1913 Webster]

            he pompous vanity of the old schoolmistress.
                                                  --Thackeray.
      [1913 Webster] -- Pom"ous*ly, adv. -- Pomp"ous*ness,
      n.
      [1913 Webster]

WordNet (r) 3.0 (2006):

pompous
    adj 1: puffed up with vanity; "a grandiloquent and boastful
           manner"; "overblown oratory"; "a pompous speech";
           "pseudo-scientific gobbledygook and pontifical hooey"-
           Newsweek [syn: grandiloquent, overblown, pompous,
           pontifical, portentous]
    2: characterized by pomp and ceremony and stately display [syn:
       pompous, ceremonious]

Moby Thesaurus II by Grady Ward, 1.0:

147 Moby Thesaurus words for "pompous":
   Gongoresque, Johnsonian, Latinate, affected, arrogant, assured,
   aureate, awkward, bedizened, big-sounding, bloated, boastful,
   bombastic, braggart, ceremonial, ceremonious, cocksure, conceited,
   confident, conventional, convinced, convoluted, cramped, cumbrous,
   decided, declamatory, decorous, determined, egotistical,
   elephantine, elevated, embroidered, euphuistic, exhibitionist,
   flamboyant, flaming, flashy, flatulent, flaunting, flossy, flowery,
   forced, formal, fulsome, fustian, garish, gassy, gaudy,
   grandiloquent, grandiose, grandisonant, guinde, halting, haughty,
   heavy, hieratic, high-flowing, high-flown, high-flying, high-hat,
   high-sounding, highfalutin, hoity-toity, hubristic, imperious,
   important, inflated, inkhorn, labored, labyrinthine, leaden,
   lexiphanic, liturgic, lofty, lumbering, lurid, magisterial,
   magniloquent, meretricious, narcissistic, ornate, orotund,
   ostentatious, overbearing, overblown, overconfident, overdone,
   overelaborate, overinvolved, oversure, overweening, overwrought,
   pedantic, persuaded, poised, ponderous, pontifical, positive,
   presumptuous, pretentious, proud, puffy, reassured, rhetorical,
   ritual, ritualistic, sacerdotal, secure, self-assured,
   self-centered, self-conceited, self-confident, self-important,
   self-reliant, selfish, sensational, sensationalistic, sententious,
   sesquipedalian, showy, snobbish, snooty, snotty, solemn, sonorous,
   stately, stiff, stilted, stuck-up, stuffy, sure, swollen, tall,
   tortuous, tumid, turgid, unafraid, undoubting, unfaltering,
   unhesitating, unwavering, unwieldy, uppity, vain, vainglorious,
   well-mannered, windy