[syn: nonsense(a), nonsensical]
The Collaborative International Dictionary of English v.0.48:
Nonsensical \Non*sen"si*cal\, a.
   Without sense; unmeaning; absurd; foolish; irrational;
   preposterous. -- Non*sen"si*cal*ly, adv. --
   Non*sen"si*cal*ness, n.
   [1913 Webster]
WordNet (r) 3.0 (2006):
nonsensical
    adj 1: incongruous;inviting ridicule; "the absurd excuse that
           the dog ate his homework"; "that's a cockeyed idea"; "ask
           a nonsensical question and get a nonsensical answer"; "a
           contribution so small as to be laughable"; "it is
           ludicrous to call a cottage a mansion"; "a preposterous
           attempt to turn back the pages of history"; "her
           conceited assumption of universal interest in her rather
           dull children was ridiculous" [syn: absurd, cockeyed,
           derisory, idiotic, laughable, ludicrous,
           nonsensical, preposterous, ridiculous]
    2: having no intelligible meaning; "nonsense syllables"; "a
       nonsensical jumble of words" [syn: nonsense(a),
       nonsensical]
Moby Thesaurus II by Grady Ward, 1.0:
45 Moby Thesaurus words for "nonsensical":
   Pickwickian, absurd, asinine, askew, beyond belief, bizarre,
   cockamamie, crazy, dumb, extravagant, fantastic, fool, foolish,
   grotesque, high-flown, idiotic, imbecilic, incredible, irrational,
   laughable, loony, ludicrous, mad, meaningless, monstrous, moronic,
   nutty, outrageous, outre, poppycockish, preposterous, ridiculous,
   rubbishy, screwball, screwy, senseless, silly, skimble-skamble,
   stupid, trashy, twaddling, twaddly, warped, weird, wild