The Collaborative International Dictionary of English v.0.48:
Traducer \Tra*du"cer\, n. 1. One who traduces; a slanderer; a calumniator. --Bp. Hall. [1913 Webster] 2. One who derives or deduces. [Obs.] --Fuller. [1913 Webster]WordNet (r) 3.0 (2006):
traducer n 1: one who attacks the reputation of another by slander or libel [syn: defamer, maligner, slanderer, vilifier, libeler, backbiter, traducer]