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.
   [1913 Webster]

         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:

dwindling \dwindling\ adj.
   gradually decreasing until little remains.

   Syn: tapering, tapering off.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

dwindling \dwindling\ n.
   the act or process of becoming gradually less until little
   remains; as, there is no greater sadness that the dwindling
   away of a family.

   Syn: dwindling away.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

dwindling
    adj 1: gradually decreasing until little remains [syn:
           dwindling, tapering, tapering off]
    n 1: a becoming gradually less; "there is no greater sadness
         that the dwindling away of a family" [syn: dwindling,
         dwindling away]