Slander is one of two forms of defamation, a statement that hurts a person's reputation, and must be spoken. The other form is libel, a written statement that damages reputation. The distinguishing characteristic between slander and libel is the means of delivery.
Slander is not a criminal offense, but is regarded as a civil one. Like libel, and defamation law in general, the law pertaining to slander balances different interests, which may be competing. On one hand, there is freedom of expression, but on the other, people should not suffer due to lies. In some cases, legal action may be required to address the issue.