Definition
Latin: "will not prosecute." A formal declaration entered on the record by a prosecutor in a criminal case — or, historically, by a plaintiff in a civil case — announcing that the party will not proceed further with the action, either in whole or in part.
The effect depends on scope:
1. Full nolle prosequi: Terminates the entire case against all defendants on all counts. The charge is dropped and the proceeding ends.
2. Partial nolle prosequi: Discontinues the action as to some counts only, or as to fewer than all defendants, while the remaining charges or parties proceed to trial.
A nolle prosequi is not an acquittal. It does not bar future prosecution for the same offense in most circumstances, though double jeopardy protections attach once jeopardy has attached — typically after a jury is sworn or the first witness is sworn in a bench trial.
Common Language
Modern common usage (Wiktionary): "A declaration from the attorney general ending a criminal prosecution"; more broadly, a proceeding by which a plaintiff or prosecutor ends a legal suit; also loosely, a refusal or rejection.
Historical common usage (Webster's 1913): "Will not prosecute — an entry on the record, denoting that a plaintiff discontinues his suit, or the attorney for the public a prosecution; either wholly, or as to some count, or as to some of several defendants."
The common definitions capture the basic function accurately, but they obscure two distinctions that matter for legal research: first, that a nolle prosequi is a formal procedural act with defined consequences for double jeopardy and re-prosecution, not merely an informal refusal; and second, that the term historically applied in civil as well as criminal proceedings — a dimension the modern common definitions largely erase.
Common Confusion
Nolle prosequi is frequently confused with dismissal and acquittal.
A dismissal may be entered by the court, often on grounds the prosecution cannot control (lack of jurisdiction, defective charging instrument). A nolle prosequi is entered by the prosecuting party, not the court, and reflects the prosecutor's exercise of discretion.
An acquittal is a judgment on the merits that permanently bars re-prosecution under double jeopardy. A nolle prosequi carries no such preclusive effect unless jeopardy had already attached before it was entered — in which case the constitutional analysis shifts and prosecutors cannot use a nolle prosequi to evade an adverse result.
Researchers using historical sources should also distinguish nolle prosequi from discontinuance, its civil-practice successor. Rapalje & Lawrence note that nolle prosequi "has been superseded in most cases by the modern practice of discontinuance" in civil proceedings.
Why It Matters in Research
Historical sources use nolle prosequi across both civil and criminal contexts. Modern sources use it almost exclusively in criminal practice. A researcher reading 18th or early 19th century materials — English or American — who encounters a nolle prosequi in a civil record should not assume criminal proceedings are involved.
The prosecutor's unilateral authority to enter a nolle prosequi has been significantly curtailed in modern American practice. Many jurisdictions now require court approval, particularly after jeopardy has attached or after a certain stage of proceedings. Historical dictionary sources — including Black's and Bouvier's — describe the attorney general's power as largely unfettered, especially before a jury is impanelled. Researchers applying historical doctrine to modern questions must account for this shift.
The Latin abbreviation "nol. pros." appears frequently in historical court records, docket entries, and reporters. Researchers working with digitized court records or clerk's minutes should search both the full Latin phrase and the abbreviation.
The entry of a nolle prosequi before jeopardy attaches versus after is a recurring constitutional pivot point in modern case law. Historical dictionary entries predate the constitutional doctrine as it developed through 20th century Supreme Court interpretation and will not reflect it.
In corpus research, nolle prosequi often appears clustered with entries on discontinuance, dismissal, and double jeopardy — follow those cross-links to trace the doctrinal evolution from common law pleading into modern procedure.
Historical Dictionary Support
The historical sources agree on the core definition: a formal record entry by a plaintiff or prosecutor declaring an intention not to proceed further, either wholly or partially. Black's (both editions), Bouvier's, Burrill's, and Rapalje & Lawrence are consistent on this.
Bouvier's adds an important procedural detail often absent in the others: in criminal cases, the attorney general may enter a nolle prosequi without the defendant's consent — both before a jury is impanelled and, notably, after conviction. This post-conviction use is a dimension modern sources rarely emphasize and that researchers working in historical criminal records should note.
Burrill's derivation note — that the term comes from "the emphatic words in the old forms, the plaintiff declaring that he will not further prosecute his suit" — is useful context for understanding why the entry must appear on the record rather than being communicated informally.
Rapalje & Lawrence are the most candid about the term's declining civil-law role, observing that discontinuance has superseded it in most civil cases. Black's and Bouvier's describe civil applicability without flagging this displacement, which can mislead researchers assuming the term remained equally operative in civil practice throughout the 19th century.
None of the historical sources engage with double jeopardy implications in any developed way — that analysis belongs to later constitutional development and will not be found in these dictionary entries.
Jurisdictional Note
American states vary significantly on whether a nolle prosequi requires court approval and at what stage prosecutor discretion ends. Federal practice under Rule 48 of the Federal Rules of Criminal Procedure requires leave of court to dismiss an indictment, information, or complaint. Researchers should not assume historical common law rules about unilateral prosecutorial authority reflect current practice in any particular jurisdiction.