The Collaborative International Dictionary of English v.0.48:

Disorganize \Dis*or"gan*ize\, v. t. [imp. & p. p.
   Disorganized; p. pr. & vb. n. Disorganizing.] [Pref. dis-
   + organize: cf. F. d['e]sorganiser.]
   To destroy the organic structure or regular system of (a
   government, a society, a party, etc.); to break up (what is
   organized); to throw into utter disorder; to disarrange.
   [1913 Webster]

         Lyford . . . attempted to disorganize the church.
                                                  --Eliot
                                                  (1809).
   [1913 Webster]

WordNet (r) 3.0 (2006):

disorganized
    adj 1: lacking order or methodical arrangement or function; "a
           disorganized enterprise"; "a thousand pages of muddy and
           disorganized prose"; "she was too disorganized to be an
           agreeable roommate" [syn: disorganized, disorganised]
           [ant: organized]

Moby Thesaurus II by Grady Ward, 1.0:

63 Moby Thesaurus words for "disorganized":
   amiss, anarchial, anarchic, anarchistic, antinomian, askew, awry,
   balled-up, bothered, chaotic, cockeyed, confused, convulsed,
   deranged, disarranged, discomfited, discomposed, disconcerted,
   dislocated, disordered, disorderly, disturbed, embarrassed,
   flustered, fluttered, fussed, haywire, in a jumble, in a pother,
   in a pucker, in a stew, in a sweat, in a swivet, in a tizzy,
   in disorder, jumbled, misplaced, mixed-up, nihilistic,
   on the fritz, out of gear, out of joint, out of kelter,
   out of kilter, out of order, out of place, out of tune,
   out of whack, perplexed, perturbed, put-out, rattled, roily,
   ruffled, shaken, shook, shuffled, syndicalistic, turbid, turbulent,
   unruly, unsettled, upset