Definition
Collusion is a secret agreement between two or more persons to use deception, legal forms, or cooperative pretense to defraud a third party or obtain an outcome that law or justice would otherwise deny. The agreement is the heart of the offense: parties whose interests appear adverse or independent act in coordinated bad faith toward a shared improper purpose.
Collusion arises across multiple legal contexts:
(1) General fraud. Two or more parties secretly cooperate to deprive a third person of legal rights — using litigation, contracts, or other legal machinery as the instrument of the scheme.
(2) Divorce law. An agreement between spouses, express or implied, in which one party commits, simulates, or allows to be represented as committed an act constituting grounds for divorce, so that the other party may obtain a divorce the court would not grant if it understood the true facts. Collusion of this kind historically operated as an absolute bar to divorce in courts of equity and ecclesiastical courts, on the theory that the court was being used as an instrument of the parties' private arrangement rather than as a forum for genuine grievance.
(3) Antitrust and commercial law. A private arrangement between competitors — typically on price, output, or market division — that suppresses genuine competition. This usage developed largely after the principal historical dictionaries were written and is now among the most common applications of the term.
Common Language
Modern common usage (Wiktionary): A private, cooperative agreement between groups that otherwise maintain the pretense of competition, contention, or non-cooperation; a private agreement for a fraudulent or illegal purpose; conspiracy.
Historical common usage (Webster's 1913): A secret agreement and cooperation for a fraudulent or deceitful purpose; a playing into each other's hands; deceit; fraud; cunning.
The common and legal definitions are unusually close for a legal term. The meaningful distinction is structural: common usage emphasizes the secretive cooperation and general fraudulent flavor, while the legal definition insists on a specific mechanism — the use of legal forms, proceedings, or formal institutions as the vehicle of the deception. Collusion in law is not mere dishonest agreement; it is dishonest agreement weaponized through the machinery of courts or law. The antitrust sense, now dominant in commercial and regulatory discourse, extends the concept beyond courts to market institutions.
Common Confusion
COLLUSION VS. CONSPIRACY VS. CONNIVANCE
These three terms are frequently used interchangeably in both ordinary language and historical legal sources, but they are not synonymous. Conspiracy is a broader agreement to commit an unlawful act, with or without use of legal forms; it does not require the pretense of adverse interests and reaches criminal as well as civil wrongs. Collusion specifically implies a feigned conflict or apparent adversity — the parties appear to be opposed or independent but are secretly cooperating. Connivance is narrower still: in divorce law, connivance is one spouse's passive consent to or procurement of the other's misconduct, distinct from active agreement. Bouvier and Black both treat connivance as a related but separate bar to divorce relief. Historical sources sometimes blur collusion and connivance; researchers must read context carefully.
Why It Matters in Research
Researchers using the Law Mind corpus will encounter collusion most heavily in three areas, each with distinct navigational considerations.
In divorce records and treatises predating no-fault divorce reform (post-1970 in most U.S. jurisdictions), collusion is a defense — a reason courts denied divorce. The historical record is heavily shaped by this context, and many of the most detailed treatments of collusion in primary sources are found in ecclesiastical court opinions and mid-nineteenth-century American divorce treatises, not in criminal or commercial materials. The definition in Black's (both editions) leads with the fraud-on-court framing, which reflects this divorce-law centrality.
In equity and common law pleading sources, collusion appears as a basis for voiding judgments, conveyances, and agreements. A judgment obtained by collusion between the nominal parties was not binding on the defrauded third party. This principle appears frequently in older equity reporters and underlies the historical dictionaries' consistent emphasis on "forms of law" as the instrument.
In antitrust and competition law materials from the twentieth century onward, the term shifts toward market cooperation among competitors. This usage is largely absent from the historical shelf sources and will be found instead in regulatory materials, federal case law, and treatises on trade regulation. Researchers working on antitrust history should not expect the historical dictionaries to illuminate the modern commercial meaning.
The Rapalje & Lawrence excerpt in the source material does not yield a direct collusion definition — it appears to be a cross-reference artifact relating to customs collectors. Researchers should treat that source as unhelpful on this term and rely on Black's, Bouvier's, and Burrill's for historical doctrinal content.
Historical Dictionary Support
The historical dictionaries converge on a core definition: collusion is a deceitful compact between two or more persons to use legal forms or proceedings to defraud a third party or obtain an outcome justice would deny. Black's (1st and 2nd editions) and Burrill's share nearly identical language tracing to Cowell's legal lexicon, defining the core form as one party bringing an action against another "for some evil purpose, as to defraud a third party of his right." This lineage suggests a formulaic definition that passed through English legal lexicography largely unchanged.
Bouvier's broadens slightly, framing collusion as any agreement "to obtain an object forbidden by law" — not limited to litigation — and expressly states that "collusion and fraud of every kind vitiate all acts which are infected with them, and render them void." This formulation is more sweeping than Black's and aligns collusion with a general equity principle rather than a narrowly procedural one.
Burrill adds the Latin derivation (collusio, from colludere, to play together) and follows Black's core text. The "playing together" image — present also in Webster's 1913 ("playing into each other's hands") — usefully captures the performative quality of collusion: the parties act as adversaries for an audience while secretly cooperating.
None of the historical dictionaries address the antitrust or commercial competition sense of the term. That gap is significant: researchers should not assume that pre-twentieth-century dictionary definitions reflect the modern regulatory meaning.
Jurisdictional Note
In U.S. family law, collusion as a divorce bar was abolished or rendered moot when no-fault divorce was adopted across the states during the 1970s and 1980s. In competition law, collusion carries specific meanings under federal antitrust statutes and parallel state law, with criminal exposure under the Sherman Act for hard-core cartel conduct. International jurisdictions vary considerably in how collusion is defined and prosecuted in competition contexts.