Source : Webster's Revised Unabridged Dictionary (1913)

Tattling \Tat"tling\, a.
   Given to idle talk; apt to tell tales. -- {Tat"tling*ly},
   adv.

Tattle \Tat"tle\, v. i. [imp. & p. p. {Tattled}; p. pr. & vb. n.
   {Tattling}.] [Akin to OE. tateren, LG. tateln, D. tateren to
   stammer, and perhaps to E. titter.]
   1. To prate; to talk idly; to use many words with little
      meaning; to chat.

            The tattling quality of age, which is always
            narrative.                            --Dryden.

   2. To tell tales; to communicate secrets; to be a talebearer;
      as, a tattling girl.

Source : WordNet®

tattling
     adj : prone to communicate confidential information [syn: {blabbermouthed},
            {leaky}, {talebearing(a)}, {tattling(a)}]