The Collaborative International Dictionary of English v.0.48:

Buncombe \Bun"combe\, Bunkum \Bun"kum\, n. [Buncombe a county of
   North Carolina.]
   Speech-making for the gratification of constituents, or to
   gain public applause; flattering talk for a selfish purpose;
   anything said for mere show. [Cant or Slang, U.S.]
   [1913 Webster]

         All that flourish about right of search was bunkum --
         all that brag about hanging your Canada sheriff was
         bunkum . . . slavery speeches are all bunkum.
                                                  --Haliburton.
   [1913 Webster]

   To speak for Buncombe, to speak for mere show, or
      popularly.
      [1913 Webster]

   Note: "The phrase originated near the close of the debate on
         the famous `Missouri Question,' in the 16th Congress.
         It was then used by Felix Walker -- a na["i]ve old
         mountaineer, who resided at Waynesville, in Haywood,
         the most western country of North Carolina, near the
         border of the adjacent county of Buncombe, which formed
         part of his district. The old man rose to speak, while
         the house was impatiently calling for the `Question,'
         and several members gathered round him, begging him to
         desist. He persevered, however, for a while, declaring
         that the people of his district expected it, and that
         he was bound to `make a speech for Buncombe.'" --W.
         Darlington.
         [1913 Webster]

WordNet (r) 3.0 (2006):

buncombe
    n 1: unacceptable behavior (especially ludicrously false
         statements) [syn: bunk, bunkum, buncombe, guff,
         rot, hogwash]

Moby Thesaurus II by Grady Ward, 1.0:

79 Moby Thesaurus words for "buncombe":
   Washingtonese, adulation, balls, baloney, big talk, bilge, blague,
   blah, blah-blah, blandishment, blarney, bop, bosh, bull, bullshit,
   bunk, bunkum, cajolement, cajolery, claptrap, compliment, crap,
   eyewash, fair words, fancy talk, fawning, federalese, fine talk,
   fish story, flam, flapdoodle, flattery, flimflam, gammon, gas,
   gobbledygook, grease, guff, gup, highfalutin, highfaluting,
   hogwash, hoke, hokum, honeyed phrases, honeyed words, hooey,
   hot air, humbug, humbuggery, incense, jiggery-pokery, malarkey,
   moonshine, official jargon, officialese, oil, palaver, piffle,
   political doubletalk, poppycock, praise, pretty lies, pussyfooting,
   rot, scat, shit, soap, soft soap, sweet nothings, sweet talk,
   sweet words, sycophancy, tall story, tall talk, tommyrot, tripe,
   wheedling, wind



U.S. Gazetteer Counties (2000):

Buncombe -- U.S. County in North Carolina
   Population (2000):    206330
   Housing Units (2000): 93973
   Land area (2000):     655.989803 sq. miles (1699.005718 sq. km)
   Water area (2000):    3.810271 sq. miles (9.868555 sq. km)
   Total area (2000):    659.800074 sq. miles (1708.874273 sq. km)
   Located within:       North Carolina (NC), FIPS 37
   Location:             35.595260 N, 82.531461 W
   Headwords:
    Buncombe
    Buncombe, NC
    Buncombe County
    Buncombe County, NC


U.S. Gazetteer Places (2000):

Buncombe, IL -- U.S. village in Illinois
   Population (2000):    186
   Housing Units (2000): 86
   Land area (2000):     1.208937 sq. miles (3.131132 sq. km)
   Water area (2000):    0.000000 sq. miles (0.000000 sq. km)
   Total area (2000):    1.208937 sq. miles (3.131132 sq. km)
   FIPS code:            09551
   Located within:       Illinois (IL), FIPS 17
   Location:             37.470987 N, 88.974935 W
   ZIP Codes (1990):     62912
   Note: some ZIP codes may be omitted esp. for suburbs.
   Headwords:
    Buncombe, IL
    Buncombe