Defamation, at a first approximation, is any form of communication that can injure a third party's reputation. This can include all modes of human-understandable communications: gestures, images, signs, words. It is not necessarily restricted to making assertions that are falsifiable, and can extend to concepts that are more abstract than reputation - like dignity and honour. For a communication to be considered defamatory, it must be conveyed to someone other than the defamed. Depending on the permanence or transience of the communication medium, defamation may be distinguished between libel (written, printed, posted online, published in mass media) and slander (spoken off the record). It is treated as a civil wrong (tort, delict), as a criminal offence, or both. The exact definition of defamation and related acts, as well as the ways they are dealt with, can vary greatly between countries and jurisdictions; for example, whether they constitute crimes or not, to what extent insults and opinions are included in addition to allegations of facts, to what extent proving the alleged facts is a valid defence.
Defamation and related laws can encompass a variety of acts (from general defamation and insult - as applicable to every citizen –, to specialized provisions covering specific entities and social structures):
Defamation against a legal person in general
Insult against a legal person in general
Acts against public officials
Acts against state institutions (government, ministries, government agencies, armed forces)
Acts against state symbols
Acts against the state itself
Acts against heads of state
Acts against religions (blasphemy)
Acts against the judiciary or legislature (contempt of court)
Defamation law has a long history stretching back to classical antiquity. While defamation has been recognized as an actionable wrong in various forms across historical legal systems and in various moral and religious philosophies, defamation law in contemporary legal systems can primarily be traced back to Roman and early English law.