The Collaborative International Dictionary of English v.0.48:

Dwindle \Dwin"dle\, v. i. [imp. & p. p. Dwindled; p. pr. & vb.
   n. Dwindling.] [From OE. dwinen to languish, waste away,
   AS. dw[imac]nan; akin to LG. dwinen, D. dwijnen to vanish,
   Icel. dv[imac]na to cease, dwindle, Sw. tvina; of uncertain
   origin. The suffix -le, preceded by d excrescent after n, is
   added to the root with a diminutive force.]
   To diminish; to become less; to shrink; to waste or consume
   away; to become degenerate; to fall away.
   [1913 Webster]

         Weary sennights nine times nine
         Shall he dwindle, peak and pine.         --Shak.
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         Religious societies, though begun with excellent
         intentions,
         are said to have dwindled into factious clubs. --Swift.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dwindle \Dwin"dle\, v. t.
   1. To make less; to bring low.
      [1913 Webster]

            Our drooping days are dwindled down to naught.
                                                  --Thomson.
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   2. To break; to disperse. [R.] --Clarendon.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dwindle \Dwin"dle\, n.
   The process of dwindling; dwindlement; decline; degeneracy.
   [R.] --Johnson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dwindle
    v 1: become smaller or lose substance; "Her savings dwindled
         down" [syn: dwindle, dwindle away, dwindle down]

Moby Thesaurus II by Grady Ward, 1.0:

124 Moby Thesaurus words for "dwindle":
   abate, ablate, attenuate, bate, be consumed, be eaten away,
   be gone, calm, calm down, cease, cease to be, cease to exist,
   close, condense, consume, consume away, contract, corrode, crumble,
   decline, decrease, deliquesce, dematerialize, depart, die,
   die away, die down, die out, diminish, disappear, dispel, disperse,
   dissipate, dissolve, dive, do a fade-out, drift away, droop, drop,
   drop off, ebb, erode, evanesce, evaporate, exit, extenuate, fade,
   fade away, fade out, fail, fall, fall away, fall off, fall short,
   flag, flee, fly, go, go away, halt, hide, languish, leave no trace,
   leave the scene, lessen, let up, lose strength, lull, melt,
   melt away, moderate, molder, move away, move off, pacify, pass,
   pass away, pass out, peak, perish, peter out, pine, plummet,
   plunge, pull away, quiesce, quiet, quieten, recede, reduce, retire,
   retire from sight, retreat, retrocede, run down, run low, sag,
   shrink, shrivel up, sink, sink away, soothe, stand off, stop,
   subside, suffer an eclipse, tail off, taper, taper off, thin,
   tranquilize, vanish, vanish from sight, wane, waste, waste away,
   weaken, wear, wear away, widen the distance, wilt, withdraw,
   wither, wither away