Definition from Nolo’s Plain-English Law Dictionary
(nol-ee pros-ee-kwee) Latin for "we shall no longer prosecute." At trial, this is an entry made on the record by a prosecutor in a criminal case or a plaintiff in a civil case stating that he will no longer pursue the matter. In a criminal case, the statement is an admission that the charges cannot be proved or that evidence has demonstrated either innocence or a fatal flaw in the prosecution's claim. An entry of nolle prosequi may be made at any time after charges are brought and before a verdict is returned or a plea entered. Most of the time, prosecutors need a judges permission to nol-pros a case.