以上三个单词均有诽镑或侵犯名誉的含义。其中，defamation (“毁誉”）是通用的法律概念，指通过向第三者传播虚假事实而致使他人(申诉者）名誉受损。其可包含两种形式的名誉诽镑，即libel和slander[1]。前者，即libel为“书面诽谤”， 指以书写的、印刷的、电影的、广播的、或其他可永久保留的形式对他人的名誉进行的诽镑[2]。而slander则为“口头诽镑”， 主要指用口头的，或其他无法保留的形式的言论破坏他人的名誉[3]。在英、美、加拿大等国，诽镑一般属于侵权责任范畴, 但依据普通法规定，如书面诽镑，即libel的内容属亵渎、猥亵、 煽动性质，则可视为犯罪被起诉[4]。相比之下，slander无论如何也构不成犯罪，此外，对slander提起侵权之诉多需旁证证明的确造成事实损害等方可[5]。
[1]“The negligent, reckless, or intentional communication to a third person of a falsehood that is injurious to the reputation of a living individual, or of a corporation or other organization. Defamation is the basis for the torts of libel and slander." Cf. James E. Clapp, Random House Webster's Dictionary of the Law, at p. 129, Random House (2000).
[2]“A defamatory statement expressed in a fixed medium, esp. writing but also a picture, sign, or electronic broadcast. " Cf. Biyan A. Gamer, Black's Law Dictionary, 7th edition ,at p. 927，West Group (1999).
[3]“A defamatory statement expressed in a transitory form, esp. speech." Id. at p. 1392.
[4]“Libel is not merely an actionable tort, but also a criminal offense. " Cf. The Publisher's Editorial Staff, Black's Law Dictionary, abridged 6th edition, at p. 1393, West Publishing Co. (1991).
[5]“ Libel is in all cases actionable pe se； but slander is，save in special cases，actionable only on proof of actual damage." Id. at p. 1393.