The Collaborative International Dictionary of English v.0.48:
Prater \Prat"er\, n. One who prates. --Shak. [1913 Webster]WordNet (r) 3.0 (2006):
prater n 1: an obnoxious and foolish and loquacious talker [syn: chatterer, babbler, prater, chatterbox, magpie, spouter]