The Collaborative International Dictionary of English v.0.48:

Mumbo Jumbo \Mum"bo Jum"bo\, n. [Perh. fr. the native name of an
   African god.]
   1. Among the Mandingos of the western Sudan, a bugbear by
      means of which the women are terrified and disciplined by
      societies of the men, one of whom assumes a masquerade for
      the purpose; hence, loosely, any Negro idol, fetish, or
      bugaboo.
      [Webster 1913 Suppl.]

            The miserable Mumbo Jumbo they paraded. --Dickens.
      [1913 Webster]

   2. An object of superstitious homage and fear. --Carlyle.
      [1913 Webster]

   3. Incomprehensible or senseless language, usually intended
      to avoid answering plainly, confuse a listener, or obscure
      an issue.
      [PJC]

   4. Language so arcane or obscure as to be unintelligible to
      the listener.
      [PJC]

WordNet (r) 3.0 (2006):

mumbo jumbo
    n 1: language or ritual causing, or intending to cause,
         confusion

Moby Thesaurus II by Grady Ward, 1.0:

162 Moby Thesaurus words for "mumbo jumbo":
   Mumbo Jumbo, abracadabra, absurdity, amorphousness, amphigory,
   amulet, anagoge, anagogics, anthroposophy, argot, babble,
   babblement, balderdash, bibble-babble, blabber, blather, bogey,
   bogeyman, boggart, bogle, bombast, booger, boogerman, boogeyman,
   bug, bugaboo, bugbear, bugger, cabala, cabalism, cant, charm,
   claptrap, conjuration, dark, darkness, double-talk, drivel, drool,
   escamotage, esotericism, esoterics, esoterism, esotery,
   fee-faw-fum, fetish, fiddle-faddle, fiddledeedee, flummery, fog,
   fogginess, folderol, fudge, fustian, fuzziness, fylfot, gabble,
   galimatias, gammadion, gammon, gibber, gibberish, gibble-gabble,
   gobbledygook, good-luck charm, hanky-panky, hocus-pocus,
   hokey-pokey, hoodoo, humbug, incantation, indeterminateness,
   indistinctness, jabber, jargon, jiggery-pokery, jugglery, juggling,
   juju, legerdemain, lingo, love charm, lucky bean, lucky piece,
   madstone, magic formula, magic words, mascot, mist, mistiness,
   monkey business, mummery, murk, murkiness, mystery, mysticism,
   mystification, narrishkeit, niaiserie, nonsense, obeah,
   obfuscation, obscurantism, obscuration, obscurity, occultism,
   opacity, open sesame, pack of nonsense, palaver, patois, patter,
   periapt, perplexity, philter, phraseology, phylactery, prate,
   prattle, prestidigitation, rant, rigamarole, rigmarole,
   rodomontade, rubbish, scarab, scarabaeus, scarabee, scatology,
   shapelessness, skimble-skamble, slang, sleight of hand,
   stuff and nonsense, stultiloquence, sudarium, swastika, symbolics,
   symbolism, taboo language, talisman, trash, trickery, trumpery,
   twaddle, twattle, twiddle-twaddle, unclarity, unclearness,
   unplainness, vagueness, vaporing, vernacular, veronica, vocabulary,
   voodoo, vulgar language, waffling, whammy, yoga, yogeeism,
   yogism