Defamation of character occurs when someone makes statements about another person that are injurious, false, unprivileged and published, according to Nolo. Public figures usually have to prove statements are also made with malice.
An injurious statement results in actual damage to a person's reputation, states Nolo. When a person's career is negatively affected or he is consequently harassed by the press, this may be grounds for proving injury. Defamation requires statements be objectively false, so opinions do not typically qualify as grounds for a lawsuit. Privileged communications do not qualify as grounds for defamation, so anything a person says in court or at a deposition is exempt. Legislators also enjoy this protected status, and public statements they make cannot be considered defamatory. Published statements do not necessarily have to be written, they just have to be heard or read by a third party.
Spoken defamation is called slander, and written defamation is libel, explains Nolo. It is a civil matter, not a criminal one. Courts try to balance a person's damaged reputation against the right to free speech. In the case of public figures, actual malice is a necessary component of defamation. This means a person makes a statement he knows to be demonstrably false, or he has doubts but willingly fails to check for the truth.