The Collaborative International Dictionary of English v.0.48:
Flatterer \Flat"ter*er\, n. One who flatters. [1913 Webster] The most abject flaterers degenerate into the greatest tyrants. --Addison. [1913 Webster]WordNet (r) 3.0 (2006):
flatterer n 1: a person who uses flattery [syn: flatterer, adulator]