The Collaborative International Dictionary of English v.0.48:

Gammon \Gam"mon\, v. t. [Etymol. unknown.] (Naut.)
   To fasten (a bowsprit) to the stem of a vessel by lashings of
   rope or chain, or by a band of iron. --Totten.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gammon \Gam"mon\ (g[a^]m"m[u^]n), n. [OF. gambon, F. jambon, fr.
   OF. gambe leg, F. jambe. See Gambol, n., and cf. Ham.]
   The buttock or thigh of a hog, salted and smoked or dried;
   the lower end of a flitch. --Goldsmith.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gammon \Gam"mon\ (g[a^]m"m[u^]n), v. t. [imp. & p. p. Gammoned
   (g[a^]m"m[u^]nd); p. pr. & vb. n. Gammoning.]
   To make bacon of; to salt and dry in smoke.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gammon \Gam"mon\ (g[a^]m"m[u^]n), n. [See 2d Game.]
   1. Backgammon.
      [1913 Webster]

   2. A victory in the game of backgammon in which one player
      gammons another, i. e., the winner bears off all of his
      pieces before his opponent bears off any pieces; as, he
      won the match with three gammons in a row.
      [PJC]

   3. An imposition or hoax; humbug. [Colloq.]
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gammon \Gam"mon\, v. t.
   1. To beat in the game of backgammon, before an antagonist
      has been able to get his "men" or counters home and
      withdraw any of them from the board; as, to gammon a
      person. In certain variants of the game one who gammons an
      opponent scores twice the normal value of the game.
      [1913 Webster +PJC]

   2. To impose on; to hoax; to cajole. [Colloq.] --Hood.
      [1913 Webster]

WordNet (r) 3.0 (2006):

gammon
    n 1: meat cut from the thigh of a hog (usually smoked) [syn:
         ham, jambon, gammon]
    2: hind portion of a side of bacon

Moby Thesaurus II by Grady Ward, 1.0:

156 Moby Thesaurus words for "gammon":
   absurdity, act, act a part, affect, amphigory, assume, babble,
   babblement, bacon, balderdash, balls, baloney, bamboozle, beguile,
   betray, bibble-babble, blabber, blague, blather, bluff, bombast,
   bosh, bull, bullshit, bunk, bunkum, butt, cajole, cheat on,
   chitterlings, circumvent, claptrap, cochon de lait, conjure,
   counterfeit, cover up, cracklings, crap, deceive, delude, diddle,
   dissemble, dissimulate, double-cross, double-talk, drivel, drool,
   dupe, eyewash, fake, fat back, feign, fiddle-faddle, fiddledeedee,
   flam, flimflam, flitch, flummery, folderol, forestall, four-flush,
   fudge, fustian, gabble, galimatias, get around, gibber, gibberish,
   gibble-gabble, gobbledygook, gull, ham, ham steak, haslet,
   headcheese, hoax, hocus-pocus, hogwash, hoke, hokum, hooey,
   hornswaggle, humbug, humbuggery, jabber, jambon, jambonneau,
   jargon, jiggery-pokery, juggle, lard, let down, let on,
   let on like, make a pretense, make as if, make believe, make like,
   mock, moonshine, mumbo jumbo, narrishkeit, niaiserie, nonsense,
   outmaneuver, outreach, outsmart, outwit, overreach,
   pack of nonsense, palaver, picnic ham, pieds de cochon, pig,
   pigeon, play, play a part, play one false, play possum, playact,
   pork, porkpie, prate, prattle, pretend, profess, put on,
   put something over, rant, rigamarole, rigmarole, rodomontade,
   rubbish, salt pork, sham, side of bacon, simulate, skimble-skamble,
   small ham, snow, sowbelly, string along, stuff and nonsense,
   stultiloquence, suckling pig, take in, trash, trick, trotters,
   trumpery, twaddle, twattle, twiddle-twaddle, two-time, vaporing,
   waffling