Source : Webster's Revised Unabridged Dictionary (1913)

Gibber \Gib"ber\, v. i. [imp. & p. p. {Gibbered}; p. pr. & vb.
   n. {Gibbering}.] [Akin to jabber, and gabble.]
   To speak rapidly and inarticulately. --Shak.

Gibber \Gib"ber\, n. [From {Gib} to balk.]
   A balky horse. --Youatt.

Source : WordNet®

gibber
     n : unintelligible talking [syn: {gibberish}]
     v 1: speak (about unimportant matters) rapidly and incessantly
          [syn: {chatter}, {piffle}, {palaver}, {prate}, {tittle-tattle},
           {twaddle}, {clack}, {maunder}, {prattle}, {blab}, {tattle},
           {blabber}, {gabble}]
     2: chatter inarticulately; of monkeys