Definition
A vexatious suit is a legal action brought maliciously and without probable cause, instituted not to vindicate a legitimate legal right but to harass, annoy, or injure the opposing party. The party who brings such a suit may be held liable in tort for the damages the defendant suffers as a result of being forced to defend against baseless or bad-faith litigation.
The suit need not be entirely without legal foundation to qualify as vexatious. If even a groundless portion of the action causes the defendant to suffer harm, injury, expense, or inconvenience they would not otherwise have faced, the vexatious character of that portion may give rise to liability. Three forms of proceeding have historically been recognized as capable of being vexatious: a criminal prosecution, a proceeding before a magistrate resulting in conviction, and a civil action.
Vexatious suit doctrine connects closely to the tort of malicious prosecution (in criminal contexts) and abuse of process (where the machinery of litigation is misused regardless of the outcome). In modern practice, these doctrines have largely absorbed the older language of "vexatious suit," though the phrase persists in statutes authorizing courts to sanction or restrict serial or bad-faith litigants.
Common Confusion
VEXATIOUS SUIT, MALICIOUS PROSECUTION, and ABUSE OF PROCESS are frequently treated as interchangeable, but they are distinct. Malicious prosecution focuses on wrongful initiation of a prior proceeding — criminal or civil — that has terminated in the plaintiff's favor, and requires both malice and lack of probable cause. Abuse of process addresses the misuse of legal process for an ulterior purpose after a proceeding has properly begun, regardless of its outcome or the initiating party's motive at filing. Vexatious suit is the broader, older framing that encompasses both concerns: it names the character of the litigation itself (harassing, without probable cause) rather than isolating a particular element of the wrong. In jurisdictions with vexatious litigant statutes, the term has taken on a second, procedural meaning — designating a category of repeat filers subject to court-imposed filing restrictions — which is analytically distinct from the tort.
Why It Matters in Research
Researchers working in pre-twentieth-century sources will encounter "vexatious suit" as the dominant framing for what modern practice calls malicious prosecution (civil) or abuse of process. Bouvier and contemporaneous treatises use the phrase broadly, and tracing a doctrine from older sources into modern cases requires recognizing that terminological migration.
The phrase has split into two distinct legal contexts in modern law that must be kept separate in research:
First, as a tort theory, it survives primarily under the labels malicious prosecution and wrongful use of civil proceedings. Restatement sources organize this doctrine under those headings, not under "vexatious suit," which means modern secondary sources may not surface when searching the historical term.
Second, as a statutory category, "vexatious litigant" statutes — enacted in many jurisdictions — use the term's spirit to justify pre-filing orders requiring serial abusive filers to obtain court permission before initiating new actions. These statutes are procedural and do not require proof of all elements of the underlying tort; they rest on a pattern-of-conduct finding rather than a single-suit analysis.
Researchers should also note that probable cause functions differently here than in Fourth Amendment or criminal law contexts. In the vexatious suit / malicious prosecution tort, probable cause is measured at the time the suit was filed and asks whether a reasonable person in the plaintiff's position would have believed the claim was valid. Conflating this with constitutional probable cause doctrine is a common error when reading across subject areas.
Historical Dictionary Support
Bouvier's Law Dictionary identifies vexatious suit as a tort within the broader law of torts, requiring three elements: institution of the suit maliciously, absence of probable cause, and resultant damage to the defendant. Bouvier's framing is notable in two respects. First, it expressly extends the doctrine beyond criminal prosecutions to civil actions and magistrate proceedings — a broader scope than some later authorities who confined malicious prosecution to criminal contexts. Second, Bouvier acknowledges partial groundlessness: a suit is not immune from the vexatious label simply because some of its claims had merit, provided the baseless portion caused independent harm.
What Bouvier does not address — and what later doctrine had to work out — is the favorable-termination requirement: most modern malicious prosecution doctrine requires that the prior proceeding end in favor of the party claiming harm. That requirement is absent from Bouvier's formulation, reflecting an earlier and somewhat looser conception of the doctrine. Researchers relying on Bouvier-era sources should be alert to this gap when mapping historical authority onto modern legal standards.
Jurisdictional Note
Vexatious litigant statutes vary substantially by jurisdiction. California's statutory scheme is among the most detailed, establishing formal lists of vexatious litigants and requiring prefiling orders. Other states address the problem through inherent court authority or general sanctions rules rather than dedicated statutes. In federal court, Rule 11 and 28 U.S.C. § 1927 are the primary tools, though federal courts also exercise inherent power to enjoin abusive filers. The underlying tort doctrine likewise varies: some jurisdictions require favorable termination for civil as well as criminal malicious prosecution; others do not.