Defamation is a false statement of fact that (1) is published; (2) damages or injures the reputation of another party; and (3) is made without legal excuse (defense or privilege). Defamation may be in the form of a written statement (libel) or a spoken statement (slander) and is a tort or legal wrong that may create civil liability (for money damages) for a person who makes a defamatory statement that is not privileged (e.g., made during a judicial proceeding) and for which there is no defense (such as truth or retraction).

To be actionable and subject the person making the statement to liability the statement must be published to a third party. In other words, a written or spoken statement made from one person to another that is not read or heard by a third person (or could not have been reasonably expected by the person making the statement to be read or heard by a third person) is not published and is not defamation.

In Colorado, defamation is recognized as a false statement of fact that is published, injures someone's reputation, and is made without a legal excuse. Defamation can be categorized as either libel, if it is written, or slander, if it is spoken. For a defamation claim to be actionable in Colorado, the statement must be communicated to a third party; a private exchange between two people that is not overheard or seen by others does not constitute publication. The injured party may seek civil damages if the defamatory statement is not protected by privileges, such as those statements made during judicial proceedings, and if there is no valid defense, like the truth of the statement or a retraction. Colorado law requires that the plaintiff prove the statement is false, made with the requisite level of fault, and caused damage to the plaintiff's reputation. Defamation law in Colorado aims to balance the protection of individual reputation with the First Amendment rights to free speech.