Which term defines a criminal offense of making false statements under oath?

The term that defines a criminal offense of making false statements under oath is "perjury." This legal term specifically refers to the act of intentionally providing false information while sworn to tell the truth, such as during a court proceeding or legal deposition. Perjury undermines the integrity of the judicial system, as it can influence the outcome of trials and affect the rights of others involved in legal matters.

In contrast, calumny refers to the making of false and defamatory statements about someone, which is not limited to being under oath. Obfuscation involves making something unclear or confusing, particularly in communication or speech, and does not pertain to an oath or legal context. Defamation, while related to damaging someone's reputation through false statements, does not require the statements to be made under oath and is generally a civil matter rather than a criminal one. Thus, perjury is the most accurate term for the specific offense described.