A person who mindlessly repeats what he or she has heard.(noun)
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Use "parroter" in a sentence
"It is also safer: He will never risk losing his life like Terry Loyd, or Anna Politkovskaya -he is much too valuable as a parroter of the official story line."
"While I often remind everyone because almost no one else does that professional anti-evolutionists are anything but clueless, I had no problem assuming that Coulter was indeed just a clueless parroter."
"Boynton, as always, is a mere parroter of conventional phrases, and the objections of the ladies fade imperceptibly into a pious indignation which is indistinguishable from that of the professional suppressors of vice."