Source : Webster's Revised Unabridged Dictionary (1913)

Blather \Blath"er\ (bl[a^][th]"[~e]r), v. i. & t. [imp. & p. p.
   {Blathered}; p. pr. & vb. n. {Blathering}.] [Written also
   {blether}.] [Icel. bla[eth]ra. Cf. {Blatherskite}.]
   To talk foolishly, or nonsensically. --G. Eliot.