Legal Definition of Perjury

During a trial, all participating witnesses will be required to swear an oath prior to providing testimony. When an individual swears an oath, he/she promises to provide the court with truthful facts and information. If he/she lies while he/she is under oath, he/she has committed perjury. Testimony is an essential aspect of any criminal or civil case.

The detailed accounts provided by witnesses often provide juries with the information necessary to determine the outcome of a case. Therefore, it is vital that these testimonies be accurate. In addition, a defendant may be asked to testify in his/her own trial. He/she will be asked questions regarding his/her involvement in the offense. Providing false answers to these questions is punishable under the law. Perjury is a very serious offense.

Generally, perjury occurs when an individual lies about information that is pertinent to a case while he/she is under oath. Perjury is limited to the facts that affect the results of a trial. Therefore, it is not illegal for an individual to provide false information about him/herself, such as his/her age, unless this information directly affects a case.

For example, if the case surrounds Social Security Benefits and potential Social Security fraud, an individual's age is pertinent to the case, and therefore, lying about this information is perjury. One of the most widely known examples of perjury in the United States occurred when President Bill Clinton was impeached, due to accusations that he committed perjury while under oath.