In criminal law. To make oath to that which the deponent knows to be untrue. This term is wider in its scope than “perjury,” for the latter, as a technical term, includes the idea of the oath being taken before a competent court or officer, and relating to a material issue, which is not implied by the word “forswear”.
FORSWEAR
TheLaw.com Law Dictionary & Black's Law Dictionary 2nd Ed.