Absolute privilege applies to statements made in certain contexts or in certain venues. Absolute privilege is a complete defense. When absolute privilege applies to an individual's speech, it is irrelevant as to whether the defamatory speech was false or what the speaker's intent was.
Restatement (Second) of Torts
Under the Restatement (Second) of Torts, Ch. 25, Topic 2, §§ 585-592A, absolute privilege extends to judicial officers, attorneys, jurors, witnesses in legislative proceedings, legally required publications, and statements made by a party during trial or in a pleading.