What is the term used for knowingly making false or maliciously critical comments to injure another person?

Defamation refers to the act of making false statements about another person that can cause harm to their reputation. It encompasses both written statements (libel) and spoken statements (slander). In the context of this question, the specified actions involve knowingly making false or malicious comments intended to injure someone.

Defamation as a broader category includes both libel and slander; libel pertains specifically to written defamation, while slander pertains to spoken defamation. The focus on the act of knowingly making false statements reflects the malicious intent associated with defamation. Therefore, the use of the term defamation in this context accurately captures the comprehensive nature of the behavior described.

The other terms, like injury, do not specifically address the aspect of malicious intent in making false statements that target someone's reputation, while libel and slander are more specific forms of defamation rather than the overarching term. Thus, defamation is the most suitable term for the action described in the question.