The Collaborative International Dictionary of English v.0.48:

Prate \Prate\, v. i. [imp. & p. p. Prated; p. pr. & vb. n.
   Prating.] [Akin to LG. & D. praten, Dan. prate, Sw. & Icel.
   prata.]
   To talk much and to little purpose; to be loquacious; to
   speak foolishly; to babble.
   [1913 Webster]

         To prate and talk for life and honor.    --Shak.
   [1913 Webster]

         And make a fool presume to prate of love. --Dryden.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Prate \Prate\, v. t.
   To utter foolishly; to speak without reason or purpose; to
   chatter, or babble.
   [1913 Webster]

         What nonsense would the fool, thy master, prate,
         When thou, his knave, canst talk at such a rate !
                                                  --Dryden.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Prate \Prate\, n. [Akin to LG. & D. praat, Sw. prat.]
   Talk to little purpose; trifling talk; unmeaning loquacity.
   [1913 Webster]

         Sick of tops, and poetry, and prate.     --Pope.
   [1913 Webster]

WordNet (r) 3.0 (2006):

prate
    n 1: idle or foolish and irrelevant talk [syn: prate,
         prattle, idle talk, blether, chin music]
    v 1: speak (about unimportant matters) rapidly and incessantly
         [syn: chatter, piffle, palaver, prate, tittle-
         tattle, twaddle, clack, maunder, prattle, blab,
         gibber, tattle, blabber, gabble]

Moby Thesaurus II by Grady Ward, 1.0:

110 Moby Thesaurus words for "prate":
   absurdity, amphigory, babble, babblement, balderdash, bavardage,
   bibble-babble, blab, blabber, blah-blah, blather, blether,
   blethers, blow, bombast, brag, bull, bullshit, cackle, caquet,
   caqueterie, chat, chatter, chitter-chatter, clack, claptrap,
   clatter, cock-a-doodle-doo, crow, dither, double-talk, drivel,
   drool, fiddle-faddle, fiddledeedee, flummery, folderol, fudge,
   fustian, gab, gabble, galimatias, gammon, gas, gasconade, gibber,
   gibberish, gibble-gabble, go on, gobbledygook, gossip, guff, gush,
   haver, hocus-pocus, hot air, humbug, idle talk, jabber, jargon,
   jaw, mere talk, mouth, mumbo jumbo, narrishkeit, natter, niaiserie,
   nonsense, nonsense talk, pack of nonsense, palaver, patter, piffle,
   pour forth, prating, prattle, prittle-prattle, puff, ramble on,
   rant, rattle, rattle on, reel off, rigamarole, rigmarole,
   rodomontade, rubbish, run on, skimble-skamble, spout, spout off,
   stuff and nonsense, stultiloquence, talk away, talk nonsense,
   talk on, talkee-talkee, tittle-tattle, trash, trumpery, twaddle,
   twattle, twiddle-twaddle, vapor, vaporing, vaunt, waffle, waffling,
   yak, yakkety-yak