Definition
To enjoin is to command or direct with legal authority. The term carries two related but directionally opposite meanings in legal usage:
1. To command performance. To require or order a person to do something. A court may enjoin a party to take affirmative action — to comply with a contract, to restore property, or to cease an ongoing wrong by active remedy.
2. To restrain or prohibit. More commonly in modern practice, to prohibit a person from doing or continuing to do a specific act. This is the operative sense when a court issues an injunction: the enjoined party is ordered to stop, to desist, or to refrain from particular conduct.
Both senses share the same core: a direct judicial command addressed to a specific person or entity, enforceable by contempt. The distinction is whether the order compels action (mandatory injunction) or forbids action (prohibitory injunction). In everyday legal usage, "enjoined" most often means restrained or prohibited.
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Common Language
Modern common usage (Wiktionary): To lay upon as a command; to direct with authority; to order or charge. Also, to prohibit or restrain by judicial order.
Historical common usage (Webster's 1913): To lay upon as an order or command; to give an injunction to; to direct with authority. Also, to prohibit or restrain by judicial decree.
The common meaning — issuing a command — maps reasonably onto one legal sense of the word, but the ordinary reader will miss the critical ambiguity. In common English, "enjoin" typically suggests commanding someone to do something. In legal practice, the dominant use is the opposite: restraining someone from doing something. A non-lawyer reading "the defendant was enjoined" will likely understand it correctly, but a non-lawyer reading "enjoin compliance" may not realize this is the less common legal usage. The directional ambiguity is real and has produced interpretive disputes in older instruments.
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Common Confusion
Enjoin vs. Restrain. These terms are often used interchangeably in equity practice, but they are not identical in scope. To restrain historically referred to a temporary or immediate check on conduct, often via a temporary restraining order. To enjoin carries broader force and is associated with the formal injunctive order of a court of equity. In modern usage the distinction has largely collapsed, but in historical sources — particularly pre-twentieth-century equity pleading — the terms can signal different procedural postures.
Enjoin vs. Compel. Because enjoin covers both mandatory and prohibitory directions, researchers occasionally conflate enjoining a party with compelling them. Mandamus compels; injunction enjoins. A court cannot substitute an injunction for mandamus where the writ of mandamus is the proper remedy. The terms operate in overlapping but distinct doctrinal spaces.
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Why It Matters in Research
The bidirectional ambiguity of enjoin is the primary research trap. In older equity opinions and pleadings, enjoin may mean either to command affirmative conduct or to restrain it. Context — and the nature of the relief sought — must resolve which sense applies. Do not assume prohibition without checking the procedural posture of the case.
Corpus researchers should be aware that enjoin appears across three distinct procedural phases: in prayer-for-relief language (the complainant asks the court to enjoin the defendant), in the court's order (the defendant is hereby enjoined), and in appellate review (whether the lower court properly enjoined the party). The word's meaning is consistent across these phases, but its legal weight differs: a request to enjoin is not an injunction, and an injunction is not self-executing.
Jurisdictional and historical variation matters here. Before the merger of law and equity under the Federal Rules of Civil Procedure (1938), enjoin was strictly equity terminology. In pre-merger sources, encountering enjoin signals that you are in equity practice, with all that implies for procedural rules, standards of proof, and available remedies. Post-merger, the term persists but operates within unified civil procedure.
In criminal and regulatory contexts, enjoin appears in enforcement actions where agencies seek to enjoin ongoing violations of law. The standard for such injunctions can differ significantly from private civil litigation — researchers crossing from private to public law should not assume identical standards apply.
The Bouvier entry is noteworthy for illustrating the affirmative sense: private citizens are said to be enjoined by law to arrest a felon present at commission of a crime. This usage — enjoined by the law itself rather than by court order — reflects a broader historical sense that has substantially faded from modern legal vocabulary but may appear in older statutes and treatises.
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Historical Dictionary Support
The historical dictionaries converge on the dual meaning without fully resolving it. Black's (both editions) leads with the affirmative sense — "require; command; positively direct" — before pivoting to the injunction context. Burrill is the most explicit about the two valences, defining enjoin first as to "impose or lay upon a command" and then specifically as to "command a person to refrain from doing a thing." Rapalje & Lawrence, characteristically compressed, treats enjoin almost entirely as a term of equity practice and points readers to the entry for injunction. Bouvier's is the most interesting because it preserves the older, non-equitable sense of enjoin in the context of citizen's arrest law, demonstrating that the word once operated with full force outside the equity courtroom.
None of the historical dictionaries explicitly flags the potential for confusion between the affirmative and prohibitory senses. That gap falls to the researcher to navigate. The 2nd edition of Black's adds case citations (Clifford v. Stewart; Lawrence v. Cooke) that the 1st edition lacks, a useful indicator that by the time of the 2nd edition the term had accumulated enough interpretive friction to warrant grounding in authority.
Anderson's entry — simply "See INJUNCTION" — is a reminder that by the late nineteenth century, the procedural home of the word was sufficiently settled that the dictionary considered a cross-reference adequate.
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Jurisdictional Note
Federal equity practice since 1938 governs enjoin under the Federal Rules of Civil Procedure, specifically Rule 65. State courts retain their own injunction standards, and the threshold for obtaining an injunction — particularly in mandatory vs. prohibitory form — varies by jurisdiction. Some states apply a higher standard for mandatory injunctions than for prohibitory ones, making the directional sense of enjoin consequential at the threshold stage of litigation.
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Encyclopedia Cross-Reference
Law Mind Encyclopedia — Injunctions
Law Mind Encyclopedia — Equitable Remedies
Law Mind Encyclopedia — Temporary Restraining Orders and Preliminary Relief
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