Source : Webster's Revised Unabridged Dictionary (1913)

Voluble \Vol"u*ble\, a. [L. volubilis, fr. volvere, volutum, to
   roll, to turn round; akin to Gr. ? to infold, to inwrap, ? to
   roll, G. welle a wave: cf. F. voluble. Cf. F. {Well} of
   water, {Convolvulus}, {Devolve}, {Involve}, {Revolt}, {Vault}
   an arch, {Volume}, {Volute}.]
   1. Easily rolling or turning; easily set in motion; apt to
      roll; rotating; as, voluble particles of matter.

   2. Moving with ease and smoothness in uttering words; of
      rapid speech; nimble in speaking; glib; as, a flippant,
      voluble, tongue.

            [Cassio,] a knave very voluble.       --Shak.

   Note: Voluble was used formerly to indicate readiness of
         speech merely, without any derogatory suggestion. ``A
         grave and voluble eloquence.'' --Bp. Hacket.

   3. Changeable; unstable; fickle. [Obs.]

   4. (Bot.) Having the power or habit of turning or twining;
      as, the voluble stem of hop plants.

   {Voluble stem} (Bot.), a stem that climbs by winding, or
      twining, round another body. -- {Vol"u*ble*ness}, n. --
      {Vol"u*bly}, adv.

Source : WordNet®

voluble
     adj : marked by a ready flow of speech; "she is an extremely
           voluble young woman who engages in soliloquies not
           conversations" [ant: {taciturn}]