Definition
To harass, disturb, or annoy a party through legal process — particularly by subjecting them to repeated or meritless litigation involving the same facts or claims already adjudicated. In legal usage, *vex* is less a standalone term than the root of a cluster of operative legal concepts: vexatious litigation, vexatious suit, and the constitutional and common law protections against being twice vexed for the same offense.
The term carries two related but distinct applications in legal sources:
1. **Procedural harassment**: Bringing repeated suits, motions, or prosecutions on facts already tried, with the purpose or effect of burdening an opposing party rather than seeking genuine relief.
2. **Constitutional dimension**: In criminal law, the double jeopardy doctrine rests on the principle that no person shall be twice put in jeopardy — twice *vexed* — for the same offense. The Latin formulation *nemo debet bis vexari* ("no one ought to be twice vexed") is the doctrinal ancestor of modern double jeopardy protections.
Common Language
**Modern common usage (Wiktionary):** A trouble.
**Historical common usage (Webster's 1913):** To make angry or annoyed by little provocations; to irritate; to plague; to torment; to harass; to afflict; to trouble; to tease. Also (rarely): to twist or weave.
The gap matters. In ordinary speech, *vex* implies irritation — an emotional state, often minor. In legal usage, the word is clinical and structural: it describes what abusive or repeated litigation *does* to a party, regardless of emotional effect. A litigant can be legally vexed by a suit that causes them no personal annoyance whatsoever. The legal meaning is about subjection to process, not about feelings.
Common Confusion
*Vex* is sometimes treated as synonymous with *harass* in legal contexts, but the terms occupy different registers. Harassment in modern law often carries specific statutory definitions tied to conduct, communications, or protected characteristics. *Vex*, by contrast, operates almost entirely within the procedural law of litigation abuse and the criminal law of double jeopardy. A harassing phone call does not vex in the legal sense; a second malicious prosecution on settled facts does.
Why It Matters in Research
Researchers will rarely encounter *vex* as a standalone term in modern legal materials. Its significance lies in what it anchors. The *nemo debet bis vexari* maxim is the doctrinal thread connecting historical common law pleading, equity's jurisdiction to restrain multiplicitous suits, and modern constitutional double jeopardy doctrine. When reading historical equity opinions or early common law treatises, *vex* and *vexation* often signal that a court is invoking this maxim — sometimes without naming it explicitly.
In historical sources, watch for contextual slippage: courts and dictionaries use *vex* to cover both civil harassment by litigation and the criminal double jeopardy principle, without always distinguishing them. The civil and criminal applications have different remedies (injunction versus plea in bar, respectively) and different procedural triggers. Conflating them in research produces errors when tracing doctrinal lineage.
Anderson's entry is the most careful of the three historical dictionaries on this point, specifying that *vex* in the prosecutorial context requires a prior proceeding that reached the merits — acquittal or conviction. This limitation is critical: a dismissal on procedural grounds historically did not vex in the double jeopardy sense, and much of the complexity in modern double jeopardy law still turns on what counts as a proceeding that has gone far enough to trigger the protection.
For corpus research, *vex* functions as a gateway term. Locating it in historical pleadings or equity bills often signals the presence of a vexatious suit claim or a double jeopardy plea nearby. Follow the thread to *vexatious*, *vexari*, and *nemo debet bis vexari* to build the full doctrinal picture.
Historical Dictionary Support
Black's Law Dictionary (both the first and second editions) defines *vex* identically and briefly: to harass, disquiet, or annoy, specifically by repeated litigation on the same facts. Neither edition elaborates on the constitutional dimension or the *nemo debet bis vexari* maxim, treating the term as essentially procedural shorthand.
Anderson's Dictionary of Law is more precise and more useful. It anchors the term explicitly to post-verdict repeat prosecution — "after another has been fairly tried on the merits and a verdict of acquittal or conviction rendered" — and cross-references *VEXARI*, pointing the researcher toward the Latin maxim and its fuller doctrinal context. Anderson also flags *vexatious litigation* as the term's most common operational form, which accurately reflects how courts and practitioners deploy the concept.
What all three historical dictionaries miss: the constitutional elevation of the *nemo debet bis vexari* principle into the Fifth Amendment's Double Jeopardy Clause, and the extensive body of doctrine distinguishing when a defendant has been "put in jeopardy" sufficient to trigger the protection. Historical dictionaries treat *vex* as a word of civil procedure; modern doctrine requires understanding it as a constitutional term of art as well.
Encyclopedia Cross-Reference
See: *Vexatious Litigation* (civil harassment by repeated suits; injunctive relief; vexatious litigant statutes)
See: *Double Jeopardy* (*nemo debet bis vexari*; Fifth Amendment; attachment of jeopardy)