Defamation (also known as calumny, vilification, libel, slander, or traducement) is the oral or written communication of a false statement about another that unjustly harms their reputation and usually constitutes a tort or crime. In several countries, including South Korea, a true statement can also be considered defamation.

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. In the United States, false light laws protect against statements which are not technically false but are misleading.

In some jurisdictions, defamation is also treated as a crime. 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  should consider the decriminalization of libel". In Saudi Arabia, defamation of the state, or a past or present ruler, is punishable under terrorism legislation.

Overview.

As of 2017, at least 130 UNESCO member states retained criminal defamation laws. In 2017, the Organization for Security and Cooperation in Europe (OSCE) Office of the Representative on Freedom of the Media issued a report on criminal defamation and anti-blasphemy laws among its member states, which found that defamation is criminalized in nearly three-quarters (42) of the 57 OSCE participating states. Many of the laws pertaining to defamation include specific provisions for harsher punishment for speech or publications critical of heads of state, public officials, state bodies and the state itself. The OSCE report also noted that blasphemy and religious insult laws exist in around one third of OSCE participating states; many of these combine blasphemy and religious insult with elements of hate speech legislation.

In Africa, at least four member states decriminalized defamation between 2012 and 2017. The ruling by the African Court of Human and Peoples’ Rights in Lohé Issa Konaté v the Republic of Burkina Faso set a precedent in the region against imprisonment as a legitimate penalty for defamation, characterizing it as a violation of the African Charter on Human and Peoples’ Rights (ACHPR), the International Covenant on Civil and Political Rights (ICCPR) and the treaty of the Economic Community of West African States (ECOWAS).

Countries in every region have moved to advance the criminalization of defamation by extending legislation to online content. Cybercrime and anti-terrorism laws passed throughout the world have led to bloggers appearing before courts, with some serving time in prison. The United Nations, OSCE, Organisation of American States (OAS) and African Commission on Human and Peoples’ Rights Special Rapporteurs for Freedom of Expression stated in a joint declaration in March 2017 that "general prohibitions on the dissemination of information based on vague and ambiguous ideas, including 'false news' or 'non-objective information', are incompatible with international standards for restrictions on freedom of expression...and should be abolished."