Extrinsic fraud is fraud that "induces one not to present a case in court or deprives one of the opportunity to be heard [or] is not involved in the actual issues ...." It can involve fraud on the court, but is not necessarily the same.
More broadly, it is defined as:
fraudulent acts which keep a person from obtaining information about his/her rights to enforce a contract or getting evidence to defend against a lawsuit. This could include destroying evidence or misleading an ignorant person about the right to sue. Extrinsic fraud is distinguished from "intrinsic fraud," which is the fraud that is the subject of a lawsuit.—Legal Explanations website.
Extrinsic fraud does not mean merely lying or perjury, nor misrepresentations, nor intrinsic fraud, nor "to matters that could have been raised during the divorce proceeding." It must involve "collateral ... circumstances" such as:
- "bribery of a judge or juror,"
- "fabrication of evidence by an attorney,"
- "preventing another party's witness from appearing,"
- "intentionally failing to join a necessary party," or
- "misleading another party into thinking a continuance had been granted...."
Paternity cases are sometimes the subject of extrinsic fraud; the classic case is when a man is encouraged to sign an acknowledgment that he is the father of a newborn baby, thus giving up his right to contest the matter in a filiation action. In Love v. Love, the Nevada Supreme Court ruled that extrinsic fraud had led the putative father to sign an admission against his interest, thus allowing the court to grant equitable relief to undo the fraud.  It also may occur when a man fails to appear in court when a paternity suit is filed against him, thus resulting in a default judgment due to the fraud by his "paramour".
In such cases, there is a high burden of proof (typically moral certainty or beyond a reasonable doubt) of the petitioner to prove the intrinsic fraud, because of the state's interest "in the best interests of the child" to ensure that every child has a father. That is called paternity by estoppel, in which the putative father is actually prevented from proving he is not the father due to the high standard of evidence necessary as a matter of law.
A lawyer who intentionally keeps information from his client about an upcoming hearing or trial could be held responsible for extrinsic fraud, as well as being subject to disciplinary action and a legal malpractice lawsuit. 
- Lawyers.com glossary. Retrieved September 15, 2008.
- See also InfoPlease website and Lexic.us website. Retrieved September 15, 2008.
- Victims of Law website. Retrieved September 15, 2008.
- Legal Explanations website. See also Law Dictionary.com website, The Free Dictionary website, and Find Articles website. Retrieved September 10, 2008.
- Ellett v. Ellett, No. 0824-00-2, Virginia, (Cir. Ct. Richmond City 2001), with cases cited therein, found at Virginia state courts website. Retrieved September 15, 2008.
- Delta Bravo website, and cases cited therein. Retrieved September 15, 2008.
- Love v. Love, 114 Nev. 572, 959 P.2d 523 (1998).
- Denise G. Callahan, "Insufficient evidence of extrinsic fraud leads to reversal in W." Daily Record and the Kansas City Daily News-Press, October 7, 2005, found at Find Articles website. "In the best interest of a child, the state of Missouri defended a mother who fooled a man into thinking he had fathered a son. In State of Missouri ex rel. Misty Lowry v. Richard Carter, the Department of Social Services, Family Support Division appealed Jackson County Judge Sandra Carol Midkiff's ruling that set aside a 1993 default paternity judgment against Carter. The Western District Court of Appeals sided with the state." Retrieved September 15, 2008.
- "What can be done about grave extrinsic fraud/unfairness by refinance lender which forced homeowner to lose home to trustee sale?", found at AVVO website. Retrieved September 15, 2008.
- See JustAnswers.com website and The Law.com. Retrieved September 15, 2008.
- articles on MongaBay.com. Retrieved September 15, 2008.
- "Equity Jurisdiction: Enjoining Execution of Criminal Judgment: Extrinsic and Intrinsic Fraud", California Law Review, Vol. 11, No. 4 (May, 1923), pp. 279-282, found atJSTOR website. Retrieved September 15, 2008.
- Richard Brenneman, "Activist Files Motion Calling UC Deal ‘Extrinsic Fraud’", Berkeley Daily Planet, June 28, 2005, found at Berkeley Daily Planet website. Retrieved September 15, 2008.