The Collaborative International Dictionary of English v.0.48:

Agitate \Ag"i*tate\, v. t. [imp. & p. p. Agitated; p. pr. &
   vb. n. Agitating.] [L. agitatus, p. p. of agitare to put in
   motion, fr. agere to move: cf. F. agiter. See Act,
   Agent.]
   1. To move with a violent, irregular action; as, the wind
      agitates the sea; to agitate water in a vessel. "Winds . .
      . agitate the air." --Cowper.
      [1913 Webster]

   2. To move or actuate. [R.] --Thomson.
      [1913 Webster]

   3. To stir up; to disturb or excite; to perturb; as, he was
      greatly agitated.
      [1913 Webster]

            The mind of man is agitated by various passions.
                                                  --Johnson.
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   4. To discuss with great earnestness; to debate; as, a
      controversy hotly agitated. --Boyle.
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   5. To revolve in the mind, or view in all its aspects; to
      contrive busily; to devise; to plot; as, politicians
      agitate desperate designs.
      [1913 Webster]

   Syn: To move; shake; excite; rouse; disturb; distract;
        revolve; discuss; debate; canvass.
        [1913 Webster]

WordNet (r) 3.0 (2006):

agitate
    v 1: try to stir up public opinion [syn: agitate, foment,
         stir up]
    2: cause to be agitated, excited, or roused; "The speaker
       charged up the crowd with his inflammatory remarks" [syn:
       agitate, rouse, turn on, charge, commove, excite,
       charge up] [ant: calm, calm down, lull, quiet,
       quieten, still, tranquilize, tranquillise,
       tranquillize]
    3: exert oneself continuously, vigorously, or obtrusively to
       gain an end or engage in a crusade for a certain cause or
       person; be an advocate for; "The liberal party pushed for
       reforms"; "She is crusading for women's rights"; "The Dean is
       pushing for his favorite candidate" [syn: crusade, fight,
       press, campaign, push, agitate]
    4: move very slightly; "He shifted in his seat" [syn: stir,
       shift, budge, agitate]
    5: move or cause to move back and forth; "The chemist shook the
       flask vigorously"; "My hands were shaking" [syn: shake,
       agitate]
    6: change the arrangement or position of [syn: agitate, vex,
       disturb, commove, shake up, stir up, raise up]

Moby Thesaurus II by Grady Ward, 1.0:

120 Moby Thesaurus words for "agitate":
   actuate, afflict, air, argue, arouse, assail, attack, beat,
   beat up, blow the coals, bother, bounce, broach, bug, burden,
   campaign, canvass, churn, churn up, concern, concuss, consider,
   convulse, debate, disarrange, discept, discombobulate, discomfit,
   discomfort, discompose, disconcert, dispute, disquiet, distract,
   distress, disturb, drive, electrify, embroil, exasperate, excite,
   fan, fan the flame, feed the fire, ferment, fire, flurry, fluster,
   flutter, foment, frazzle, fret, fuss, give concern, heat, heat up,
   impassion, impel, incense, incite, inflame, instigate, irritate,
   jar, joggle, jolt, jounce, load with care, moot, move, nettle,
   paddle, peeve, perturb, perturbate, pique, press, promote, provoke,
   psych, push, put to it, put up to, rally, rattle, rile, ripple,
   rock, roil, roughen, rouse, ruffle, rumple, set on, shake,
   shake up, shock, sic on, spook, stagger, stir, stir the embers,
   stir up, swirl, thrash out, throw, throw into confusion, tickle,
   trouble, unhinge, unnerve, unsettle, untune, upset, ventilate,
   whet, whip, whip up, whisk, work up