idiotic

idiotic
    adj 1: insanely irresponsible; "an idiotic idea" [syn:
           {crackbrained}, {idiotic}]
    2: 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}]
    3: having a mental age of three to seven years [syn: {imbecile},
       {imbecilic}, {idiotic}]
    

Idiotic \Id`i*ot"ic\, Idiotical \Id`i*ot"ic*al\, a. [L.
   idioticus ignorant, Gr. ?: cf. F. idiotique. See {Idiot}.]
   1. Common; simple. [Obs.] --Blackwall.
      [1913 Webster]

   2. Pertaining to, or like, an idiot; characterized by idiocy;
      foolish; fatuous; as, an idiotic person, speech, laugh, or
      action.
      [1913 Webster]
    

78 Moby Thesaurus words for "idiotic":
      apish, arrested, asinine, babbling, backward, batty, befooled,
      beguiled, besotted, blithering, brainless, buffoonish, burbling,
      cockeyed, crackbrained, cracked, crazy, credulous, cretinistic,
      cretinous, daffy, daft, dazed, dithering, dizzy, doting, driveling,
      drooling, dumb, fatuitous, fatuous, flaky, fond, fool, foolheaded,
      foolish, fuddled, futile, gaga, goofy, gulled, half-baked,
      half-witted, imbecile, imbecilic, inane, inept, infatuated, insane,
      kooky, loony, mad, maudlin, maundering, mentally defective,
      mentally deficient, mentally handicapped, mentally retarded,
      mongoloid, moronic, not all there, nutty, retarded, sappy, screwy,
      senseless, sentimental, silly, simple, simpleminded, simpletonian,
      slobbering, stupid, subnormal, thoughtless, wacky, wet, witless