Defamation is the act of communicating to a third party false statements about a person, place, or thing that results in damage to its reputation. It can be spoken (slander) or written (libel). It constitutes a tort or a crime. The legal definition of defamation and related acts as well as the ways they are dealt with can vary greatly between countries and jurisdictions (what exactly they must consist of, whether they constitute crimes or not, and to what extent proving the alleged facts is a valid defence).

Defamation laws can encompass a variety of acts:

• Insult against a legal person in general
• Defamation against a legal person in general
• Acts against public officials
• Acts against state institutions (e.g., government, ministries, government agencies, armed forces)
• Acts against state symbols
• Acts against the state itself
• Acts against religions (e.g., blasphemy, discrimination)
• Acts against the judiciary or legislature (e.g., contempt of court, censure)