The Collaborative International Dictionary of English v.0.48:

Dizzy \Diz"zy\, v. t. [imp. & p. p. Dizzied; p. pr. & vb. n.
   Dizzying.]
   To make dizzy or giddy; to give the vertigo to; to confuse.
   [1913 Webster]

         If the jangling of thy bells had not dizzied thy
         understanding.                           --Sir W.
                                                  Scott.

The Collaborative International Dictionary of English v.0.48:

Dizzy \Diz"zy\ (d[i^]z"z[y^]), a. [Compar. Dizzier
   (d[i^]z"z[i^]*[~e]r); superl. Dizziest.] [OE. dusi, disi,
   desi, foolish, AS. dysig; akin to LG. d["u]sig dizzy, OD.
   deuzig, duyzig, OHG. tusig foolish, OFries. dusia to be
   dizzy; LG. dusel dizziness, duselig, dusselig, D. duizelig,
   dizzy, Dan. d["o]sig drowsy, slepy, d["o]se to make dull,
   drowsy, d["o]s dullness, drowsiness, and to AS. dw[=ae]s
   foolish, G. thor fool. [root]71. Cf. Daze, Doze.]
   1. Having in the head a sensation of whirling, with a
      tendency to fall; vertiginous; giddy; hence, confused;
      indistinct.
      [1913 Webster]

            Alas! his brain was dizzy.            --Drayton.
      [1913 Webster]

   2. Causing, or tending to cause, giddiness or vertigo.
      [1913 Webster]

            To climb from the brink of Fleet Ditch by a dizzy
            ladder.                               --Macaulay.
      [1913 Webster]

   3. Without distinct thought; unreflecting; thoughtless;
      heedless. "The dizzy multitude." --Milton.
      [1913 Webster]

WordNet (r) 3.0 (2006):

dizzy
    adj 1: having or causing a whirling sensation; liable to
           falling; "had a dizzy spell"; "a dizzy pinnacle"; "had a
           headache and felt giddy"; "a giddy precipice"; "feeling
           woozy from the blow on his head"; "a vertiginous climb up
           the face of the cliff" [syn: dizzy, giddy, woozy,
           vertiginous]
    2: lacking seriousness; given to frivolity; "a dizzy blonde";
       "light-headed teenagers"; "silly giggles" [syn: airheaded,
       dizzy, empty-headed, featherbrained, giddy, light-
       headed, lightheaded, silly]
    v 1: make dizzy or giddy; "a dizzying pace"

Moby Thesaurus II by Grady Ward, 1.0:

226 Moby Thesaurus words for "dizzy":
   addle, addlebrained, addled, addleheaded, addlepated, adrift,
   afloat, alternating, amorphous, apish, asinine, babbling, ball up,
   batty, beery, befooled, befuddle, befuddled, beguiled, bemused,
   besotted, bewilder, bewildered, blear-witted, blind drunk,
   brainless, buffoonish, capricious, cause vertigo, changeable,
   changeful, cockeyed, confounded, confused, crapulent, crapulous,
   crazy, credulous, daffy, daft, dazed, dazzled, delirious,
   desultory, deviable, distracted, doting, drenched, drunk, drunken,
   dumb, eccentric, empty-headed, erratic, exorbitant, extravagant,
   extreme, faint, far-gone, fast and loose, fatuitous, fatuous,
   featherbrained, featherheaded, fickle, fitful, flaky, flickering,
   flighty, flitting, fluctuating, fluster, flustered, fluttery,
   foggy, fond, fool, foolheaded, foolish, fou, freakish, frivolous,
   fuddle, fuddlebrained, fuddled, full, futile, gaga, gay, giddy,
   giddy-brained, giddy-headed, giddy-pated, giddy-witted, glorious,
   goofy, gulled, happy, harebrain, harebrained, idiotic, imbecile,
   immoderate, impetuous, impulsive, in liquor, inane, incoherent,
   inconsistent, inconstant, indecisive, inebriate, inebriated,
   inebrious, inept, infatuated, infirm, inordinate, insane,
   intoxicate, intoxicated, irregular, irresolute, irresponsible,
   jolly, kooky, light, light-headed, lightheaded, loony, mad,
   maudlin, mazy, mellow, mercurial, merry, mix up, moody, moronic,
   muddle, muddled, muddleheaded, muddybrained, muzzy, nappy, nutty,
   off, puzzled, puzzleheaded, rambling, ranting, rattlebrained,
   rattleheaded, rattlepated, raving, reeling, restless, roving,
   sappy, scatterbrained, scramblebrained, screwy, senseless,
   sentimental, shapeless, shatterbrained, shifting, shifty, shikker,
   shuffling, silly, skittish, sodden, sotted, spasmodic, spineless,
   stupid, swimming, swirl the senses, thoughtless, throw off, tiddly,
   tipsy, tottering, towering, turned around, unaccountable,
   uncertain, unconscionable, uncontrolled, undependable,
   under the influence, undisciplined, undue, unfixed, unmeasurable,
   unpredictable, unreliable, unrestrained, unsettled, unstable,
   unstable as water, unstaid, unsteadfast, unsteady, vacillating,
   vagrant, variable, vertiginous, vicissitudinary, vicissitudinous,
   volatile, wacky, wandering, wanton, wavering, wavery, wavy,
   wayward, wet, whimsical, whirl the mind, whirling, wishy-washy,
   witless, woozy