The Collaborative International Dictionary of English v.0.48:

autistic \autistic\ adj.
   afflicted with autism.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

autistic
    adj 1: characteristic of or affected with autism; "autistic
           behavior"; "autistic children"

Moby Thesaurus II by Grady Ward, 1.0:

152 Moby Thesaurus words for "autistic":
   Barmecidal, Barmecide, acquisitive, affectless, airy,
   ambitious for self, anesthetized, apparent, apparitional, arctic,
   bashful, blunt, careerist, catatonic, chill, chilly, chimeric,
   close, cold, cold as charity, cold-blooded, coldhearted, cool,
   deceptive, delusional, delusionary, delusive, delusory, dereistic,
   dispassionate, dissociable, dreamlike, dreamy, drugged, dull,
   egotistical, emotionally dead, emotionless, erroneous, fallacious,
   false, fantastic, frigid, frosted, frosty, frozen, grasping,
   greedy, heartless, icy, idealistic, illusional, illusionary,
   illusive, illusory, imaginary, immovable, impassible, impassive,
   impractical, in the clouds, incompatible, individualistic,
   inexcitable, insociable, insusceptible, misleading, mopey, mopish,
   morose, narcissistic, nonemotional, nongregarious, objective,
   obtuse, ostensible, otherworldly, out of touch, passionless,
   personalistic, phantasmagoric, phantasmal, phantom, poetic,
   possessive, privatistic, quixotic, remote, romancing, romantic,
   romanticized, seeming, self-absorbed, self-admiring,
   self-advancing, self-besot, self-centered, self-considerative,
   self-contained, self-deceptive, self-deluding, self-devoted,
   self-esteeming, self-indulgent, self-interested, self-jealous,
   self-occupied, self-pleasing, self-seeking, self-serving,
   self-sufficient, selfish, snug, socially incompatible, soulless,
   specious, spectral, spiritless, starry-eyed, storybook, sullen,
   supposititious, transcendental, transmundane, unactual,
   unaffectionate, unclubbable, uncommunicative, uncompanionable,
   uncongenial, unemotional, unfeeling, unfounded, unfriendly,
   ungenial, unimpassioned, unimpressionable, unloving, unpassionate,
   unpractical, unreal, unrealistic, unresponding, unresponsive,
   unsociable, unsocial, unsubstantial, unsusceptible, unsympathetic,
   untouchable, visionary, wish-fulfilling