What is Defamation?

Legal Definition
Defamation—also calumny, vilification, and traducement—is the communication of a false statement that harms the reputation of an individual person, business, product, group, government, religion, or nation.

Under common law, to constitute defamation, a claim must generally be false and must have been made to someone other than the person defamed. Some common law jurisdictions also distinguish between spoken defamation, called slander, and defamation in other media such as printed words or images, called libel.

False light laws protect against statements which are not technically false, but which are misleading.

In some civil law jurisdictions, defamation is treated as a crime rather than a civil wrong. The United Nations Human Rights Committee ruled in 2012 that the libel law of one country, the Philippines, was inconsistent with Article 19 of the International Covenant on Civil and Political Rights, as well as urging that "State parties [to the Covenant] should consider the decriminalization of libel".

A person who defames another may be called a "defamer", "libeler", "slanderer", or, rarely, "famacide".
-- Wikipedia
Legal Definition
Defamation is a statement that injures a third party's reputation. The tort of defamation includes both libel (written statements) and slander (spoken statements).

To win a defamation case, a plaintiff must show four things: 1) a false statement purporting to be fact; 2) publication or communication of that statement to a third person; 3) fault; and 4) damages, or some harm caused to the person or entity who is the subject of the statement.

Since the U.S. Supreme Court's 1964 decision in First Amendment concerns. Thus, for instance, public officials and public figures (people who are famous) must show that statements were made with actual malice to recover in an action for defamation. Actual malice means that a statement was made with knowledge that it was false or with reckless disregard of whether or not it was false. In addition, a plaintiff must show actual malice by "clear and convincing" evidence rather than the usual burden of proof in a civil case, preponderance of the evidence.

A private person suing about a matter of private concern need only show negligence, meaning that the defendant knew the statement was false, or would have known if she or he had exercised reasonable care.

Defamation claims are also subject to a number of privileges. The types and limits of these privileges will vary from state to state.

An absolute privilege is a complete defense to a defamation claim. For instance, statements made by witnesses during a judicial proceedings are subject to absolute privilege. The reason is that those statements are subject to sanctions. Statements made during legislative debates are also protected by an absolute privilege.

Statements may also be protected by a qualified privilege. For instance, a parent's statement to her or his children warning them not to associate with certain kids is likely protected by a qualified privilege.
Legal Definition
Tort. The speaking slanderous words of a person so as, de bona fama aliquid detrahere, to hurt his good fame. Vide Slander.

2. In the United States, the remedy for defamation is by an action on the case, where the words are slanderous.

3. In England, besides the remedy by action, proceedings may be instituted in the ecclesiastical court for redress of the injury. The punishment for defamation, in this court, is payment of costs and penance enjoined at the discretion of the judge. When the slander has been privately uttered, the penance may be ordered to be performed in a private place; when publicly uttered, the sentence must be public, as in the church of the parish of the defamed party, in time of divine service,, and the defamer may be required publicly to pronounce that by such words, naming them, as set forth in the sentence, he had defamed the plaintiff, and, therefore, that he begs pardon, first, of God, and then of the party defamed, for uttering such words. Clerk's Assist. 225; 3 Burn's Eccl. Law, Defamation, pl. 14; 2 Chit. Pr. 471 Cooke on Def.
-- Bouviers Law Dictionary
Legal Definition
The taking from one's reputation. The offence of injuring a person's character, fame or reputation by false and malicious statements. The term seems to be comprehensive of both libel and slander. Printing Co., v. Moulden, 15 Tex. Civ. App. 574, 41 S. W. 381; Moore v. Francis, 121 N. Y. 199, 23 N. E. 1127, 8L.R.A. 214, 18 Am. St Rep. 810; Hollenbeck v. Hall, 103.Iowa, 214, 72 N. W. 518, 39 L. R. A. 734, 64 Am. St. Rep. 175; Mosnat v, Snyder, 105 Iowa, 500, 75 N. W. 356.
-- Black's Law Dictionary
Legal Definition
A false publication calculated to bring one into disrepute. See 103 Iowa, 214, 64 Am. St. Rep. 175, 39 L. R. A. 734, 72 N. W. 518.
-- Ballentine's Law Dictionary