The Collaborative International Dictionary of English v.0.48:

Nonsense \Non"sense\, n. [Pref. non- + sense: cf. F. nonsens.]
   1. That which is not sense, or has no sense; words, or
      language, which have no meaning, or which convey no
      intelligible ideas; absurdity.
      [1913 Webster]

   2. Trifles; things of no importance.
      [1913 Webster]

   Nonsense verses, lines made by taking any words which
      occur, but especially certain words which it is desired to
      recollect, and arranging them without reference to
      anything but the measure, so that the rhythm of the lines
      may aid in recalling the remembrance of the words.
      [1913 Webster]

   Syn: Folly; silliness; absurdity; trash; balderdash.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

fiddledeedee \fid"dle*dee*dee`\, interj.
   An exclamatory word or phrase, equivalent to nonsense!
   [Colloq.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

nonsense
    adj 1: having no intelligible meaning; "nonsense syllables"; "a
           nonsensical jumble of words" [syn: nonsense(a),
           nonsensical]
    n 1: a message that seems to convey no meaning [syn: nonsense,
         bunk, nonsensicality, meaninglessness, hokum]
    2: ornamental objects of no great value [syn: folderal,
       falderol, frill, gimcrackery, gimcrack, nonsense,
       trumpery]

Moby Thesaurus II by Grady Ward, 1.0:

125 Moby Thesaurus words for "nonsense":
   Greek, absurdity, absurdness, amphigory, antics, applesauce,
   babble, babblement, balderdash, baloney, bibble-babble, bilge,
   blabber, blah, blather, blatherskite, blether, bombast, bosh,
   buffoonery, bull, bullshit, bunk, bunkum, bushwa, cackle, capering,
   claptrap, cock, crap, double Dutch, double-talk, drip, drivel,
   drool, eyewash, fantasticalness, fiddle-faddle, fiddledeedee,
   flapdoodle, flimflam, flummery, folderol, foolishness, frivolity,
   fudge, fustian, gabble, galimatias, gammon, garbage, gas, gibber,
   gibberish, gibble-gabble, gobbledygook, gook, guff, hocus-pocus,
   hogwash, hokum, hooey, horsefeathers, horseplay, hot air, humbug,
   inanity, jabber, jabberwocky, jargon, jazz, jesting,
   jiggery-pokery, jokes, joking, ludicrousness, malarkey, mischief,
   monkey business, monkeyshines, monstrousness, moonshine,
   mumbo jumbo, mumbo-jumbo, narrishkeit, niaiserie, nonsensicality,
   outrageousness, pack of nonsense, palaver, piffle, poppycock,
   pranks, prate, prattle, preposterousness, puffery, punk, rant,
   ridiculousness, rigamarole, rigmarole, rodomontade, rot, rubbish,
   shenanigans, shit, silliness, skimble-skamble, stuff and nonsense,
   stultiloquence, tomfoolery, tommyrot, trash, tricks, tripe,
   trumpery, twaddle, twattle, twiddle-twaddle, vaporing, waffle,
   waffling, waggishness, wildness



Bouvier's Law Dictionary, Revised 6th Ed (1856):

NONSENSE, construction. That which in a written agreement or will is
unintelligible.
     2. It is a rule of law that an instrument shall be so construed that
the whole, if possible, shall stand. When a matter is written grammatically
right, but it is unintelligible, and the whole makes nonsense, some words
cannot be rejected to make sense of the rest; 1 Salk. 324; but when matter
is nonsense by being contrary and repugnant to, some precedent sensible
latter, such repugnant matter is rejected. Ib.; 15 Vin. Ab. 560; 14 Vin. Ab.
142. The maxim of the civil law on this subject agrees with this rule: Quae
in testamento ita sunt scripta, ut intelligi non possent: perinde sunt, ac
si scripta non essent. Dig. 50,17,73,3. Vide articles Ambiguity;
Construction; Interpretation.
     3. In pleading, when matter is nonsense by being contradictory and
repugnant to something precedent, the precedent matter, which is sense,
shall not be defeated by the repugnancy which follows, but that which is
contradictory shall be rejected; as in ejectment where the declaration is of
a demise on the second day of January, and that the defendant postea
scilicet, on the first of January, ejected him; here the scilicet may be
rejected as being expressly contrary to the postea and the precedent matter.
5 East, 255; 1 Salk. 324.



The Devil's Dictionary (1881-1906):

NONSENSE, n.  The objections that are urged against this excellent
dictionary.