The Collaborative International Dictionary of English v.0.48:

Flutter \Flut"ter\, v. t.
   1. To vibrate or move quickly; as, a bird flutters its wings.
      [1913 Webster]

   2. To drive in disorder; to throw into confusion.
      [1913 Webster]

            Like an eagle in a dovecote, I
            Fluttered your Volscians in Corioli.  --Shak.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Flutter \Flut"ter\, n.
   1. The act of fluttering; quick and irregular motion;
      vibration; as, the flutter of a fan.
      [1913 Webster]

            The chirp and flutter of some single bird --Milnes.
                                                  .
      [1913 Webster]

   2. Hurry; tumult; agitation of the mind; confusion; disorder.
      --Pope.
      [1913 Webster]

   Flutter wheel, a water wheel placed below a fall or in a
      chute where rapidly moving water strikes the tips of the
      floats; -- so called from the spattering, and the
      fluttering noise it makes.
      [1913 Webster]

WordNet (r) 3.0 (2006):

flutter
    n 1: the act of moving back and forth [syn: waver, flutter,
         flicker]
    2: abnormally rapid beating of the auricles of the heart
       (especially in a regular rhythm); can result in heart block
    3: a disorderly outburst or tumult; "they were amazed by the
       furious disturbance they had caused" [syn: disturbance,
       disruption, commotion, flutter, hurly burly, to-do,
       hoo-ha, hoo-hah, kerfuffle]
    4: the motion made by flapping up and down [syn: flap,
       flapping, flutter, fluttering]
    v 1: move along rapidly and lightly; skim or dart; "The
         hummingbird flitted among the branches" [syn: flit,
         flutter, fleet, dart]
    2: move back and forth very rapidly; "the candle flickered"
       [syn: flicker, waver, flitter, flutter, quiver]
    3: flap the wings rapidly or fly with flapping movements; "The
       seagulls fluttered overhead"
    4: beat rapidly; "His heart palpitated" [syn: palpitate,
       flutter]
    5: wink briefly; "bat one's eyelids" [syn: bat, flutter]

Moby Thesaurus II by Grady Ward, 1.0:

371 Moby Thesaurus words for "flutter":
   Bebung, addle, addle the wits, ado, agiotage, agitate, agitation,
   arbitrage, arrhythmia, asking price, ball up, barrage,
   bearish prices, beat, beat a ruffle, beat a tattoo, beating,
   becloud, bedazzle, befuddle, befuddlement, bewilder, bewilderment,
   bicker, bid price, birdies, blooping, blurping, bob, bobble,
   book value, bother, botheration, brandish, bug, bullish prices,
   burst, bustle, buying in, buzz about, call price, careen, chaos,
   closing price, cloud, coggle, commotion, confuse, confusion, dance,
   dancing, dangle, dash, daze, dazzle, decline, didder,
   discombobulate, discombobulation, discomfit, discomfiture,
   discompose, discomposure, disconcert, disconcertion, disorder,
   disorganization, disorganize, disorient, disorientation, disquiet,
   disquietude, distortion, disturb, disturbance, dither, dithers,
   drive, drum, drum music, drumbeat, drumfire, drumming, electrify,
   embarrass, embarrassment, entangle, equity capital, face value,
   falter, feedback, feery-fary, ferment, fidget, fidgetiness,
   fidgets, fit, fixed price, flap, flapping, flash price, flaunt,
   flick, flicker, flickering, flickering light, flier, flip,
   flip out, flit, flitter, float, flop, flourish, fluctuate,
   fluctuating, fluctuation, flummox, flurry, fluster, flusteration,
   flustration, flutteriness, fluttering, fly, fog, foofaraw,
   freak out on, frenzy, fret, fuddle, fuddlement, fuss, fussiness,
   get high on, glancing light, glow, go pitapat, gutter, haste,
   have the fidgets, have the shakes, haze, heartbeat, heartthrob,
   heave, heaving, helter-skelter, high, hissing, hover, howling,
   hubbub, hullabaloo, hum, hurry, hurry about, hurry-scurry, hustle,
   inquietude, issue par, issue price, jar, jerk, jolt, jumble, jump,
   lambency, lather, librate, light show, liquidation, low, lurch,
   maelstrom, make a fuss, market price, market value, maze, mess,
   mist, mix up, moider, motorboating, muddle, muddlement,
   nominal value, nutate, offering price, opening price, oscillate,
   oscillating, oscillation, palpitate, palpitation, pant, panting,
   par, par value, paradiddle, parity, patter, pendulate, perplexity,
   perturb, perturbation, pitapat, pitch, pitter-patter, play,
   play of light, plunge, pother, pound, pounding, price,
   profit taking, pucker, pulsate, pulsation, pulse, put out,
   put price, quake, quaking, quaver, quavering, quiver, quivering,
   quotation, quoted price, race, raise hell, rally, rat-a-tat,
   rat-tat, rat-tat-tat, rataplan, rattattoo, rattle, reel, resonate,
   restlessness, rhythm, rock, roll, round trade, rub-a-dub, ruff,
   ruffle, rumble, rush, rush about, rush around, scalping, scamper,
   scramble, scratching, scurry, scuttle, settling price, shake,
   shake up, shakes, shaking, shiver, shivers, shock, shredding,
   shudder, shuffle, slat, sound a tattoo, spasm, spatter,
   speculation, splatter, splutter, spot sale, spurt, sputter,
   squeals, squirm, staccato, stagger, stated value, static, stew,
   stir, stockjobbery, stockjobbing, swag, sway, sweat, swell,
   swell with emotion, swing, swings, swirl, swivet, tat-tat, tattoo,
   tear around, tempo, thrill, thrill to, throb, throbbing,
   throw into confusion, thrum, thump, thumping, tingle,
   tingle with excitement, tizzy, to-do, tom-tom, toss, toss and turn,
   tremble, trembling, tremolando, tremolant, tremolo, tremor,
   trepidation, trepidity, trill, trillet, trilleto, trillo, trouble,
   tumble, tumult, turn, turn on to, twist and turn, twitch, twitter,
   twitteration, undulate, unquiet, unrest, unsettle, unsettlement,
   upset, vacillate, vacillating, vacillation, venture,
   venture capital, vibrate, vibrato, vortex, wag, waggle, wave,
   waver, waving, whirl, whistles, whiz about, wield, wiggle, wigwag,
   wobble, woomping, wow, wowwows, wriggle, writhe