The Collaborative International Dictionary of English v.0.48:

buffoon \buf*foon"\, n. [F. bouffon (cf. It. buffone, buffo,
   buffa, puff of wind, vanity, nonsense, trick), fr. bouffer to
   puff out, because the buffoons puffed out their cheeks for
   the amusement of the spectators. See Buffet a blow.]
   A man who makes a practice of amusing others by low tricks,
   antic gestures, etc.; a droll; a mimic; a harlequin; a clown;
   a merry-andrew.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

buffoon \buf*foon"\, a.
   Characteristic of, or like, a buffoon. "Buffoon stories."
   --Macaulay.
   [1913 Webster]

         To divert the audience with buffoon postures and antic
         dances.                                  --Melmoth.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

buffoon \buf*foon"\, v. i.
   To act the part of a buffoon. [R.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Buffoon \Buf*foon"\, v. t.
   To treat with buffoonery. --Glanvill.
   [1913 Webster]

WordNet (r) 3.0 (2006):

buffoon
    n 1: a rude or vulgar fool [syn: clown, buffoon]
    2: a person who amuses others by ridiculous behavior [syn:
       clown, buffoon, goof, goofball, merry andrew]

Moby Thesaurus II by Grady Ward, 1.0:

70 Moby Thesaurus words for "buffoon":
   Columbine, Hanswurst, Harlequin, Pantalone, Pantaloon,
   Polichinelle, Pulcinella, Punch, Punchinello, Scaramouch, ass,
   bad boy, booger, born fool, buffo, bugger, clown, cutup, devil,
   doodle, egregious ass, elf, enfant terrible, figure of fun, fool,
   funmaker, harlequin, hood, hoodlum, hooligan, ignoramus, imp,
   jack-pudding, jackass, jester, joker, jokester, knave,
   little devil, little monkey, little rascal, lunatic, merry-andrew,
   milksop, minx, mischief, mischief-maker, mooncalf, motley,
   motley fool, perfect fool, pickle-herring, pixie, practical joker,
   prankster, puck, rapscallion, rascal, rogue, rowdy, ruffian, scamp,
   scapegrace, schmuck, softhead, sop, stupid ass, tomfool, wag,
   zany