Definition
In civil law, a quasi delict is a civil wrong giving rise to an obligation to repair harm caused to another, where the wrongdoer acted without malice or deliberate intent but through fault, negligence, or inexcusable imprudence. It occupies a middle category between a true delict — which requires willful or intentional wrongdoing — and conduct that is entirely blameless. The obligation to compensate arises not from agreement between the parties but from the law itself, which imposes liability on the person whose careless or imprudent act caused the injury.
The concept is a product of Roman civil law and survives as an operative category in civil law jurisdictions today, particularly in Louisiana, Quebec, France, Scotland, and other legal systems with Roman-law foundations. In common law jurisdictions, the same territory is largely occupied by the law of negligence and tort, though the structural logic differs.
Roman law recognized four canonical quasi delicts:
1. Qui judex litem suam fecit — a judge or juror who made a case his own, by showing partiality or exceeding the permitted formula in assessing damages.
2. Deiectum vel effusum — liability imposed on occupants of a building from which something was thrown or poured onto a public way, injuring a passerby.
3. Positum aut suspensum — liability for objects hung or placed in a position over a public way so as to endanger passersby, whether or not harm had yet occurred.
4. Nautae, caupones, stabularii — liability of ships' masters, innkeepers, and stable-keepers for theft or damage caused by their employees or others in their establishments, without requiring proof of the proprietor's personal fault.
These categories were illustrative rather than exhaustive. Later civil law doctrine generalized the principle: any act causing harm to another through fault — without requiring intent — could give rise to a quasi-delictual obligation.
Common Confusion
Quasi delict and quasi-contract are frequently confused because both belong to the broader Roman category of obligations arising neither from contract nor from true delict. They are distinct: a quasi-contract concerns unjust enrichment or obligations arising from a beneficial act (such as negotiorum gestio or condictio indebiti), while a quasi delict concerns harm caused through fault. One creates a duty to pay for a benefit received without authorization; the other creates a duty to compensate for an injury caused by careless conduct. Researchers working in civilian sources must hold both concepts in view, as the surrounding doctrinal discussion often treats them as paired complements.
Quasi delict should also be distinguished from delict proper. A delict requires intentional wrongdoing — the civilian analog to intentional tort. A quasi delict lacks the element of intent but still requires fault; it is not strict liability, which imposes liability without any fault requirement.
Why It Matters in Research
For researchers working in common law sources, quasi delict rarely appears except in comparative law discussions or in the law of Louisiana and other mixed jurisdictions. Do not expect to find it as an operative term in English case law or most American legal materials. Its natural habitat is civilian codes and treatises.
In Louisiana, quasi delict was the foundational concept in the state's pre-codification and codified tort law. The Louisiana Civil Code used the term directly until relatively recent revision, when the language was modernized. Researchers in Louisiana legal history will encounter quasi delict as a live doctrinal category, not a historical curiosity.
When reading Black's Law Dictionary entries across editions, note that the entry reflects the civilian framework without translating it into common law terms. The four Roman categories listed are historically specific and do not map neatly onto modern tort subcategories. A researcher who treats them as an exhaustive list will misread the later civilian development of the doctrine, which expanded well beyond the four named types.
The parallel structure of Roman obligations — contract, quasi-contract, delict, quasi delict — is important context for reading civilian treatises and codes. Missing this framework will make civilian doctrinal arguments about liability and obligation appear unmotivated. The Law Mind Contracts encyclopedia entry on quasi-contract provides the paired civilian concept that researchers will typically need alongside this entry.
Historical Dictionary Support
Black's Law Dictionary defines quasi delict as an act causing injury to another through fault, negligence, or imprudence not legally excusable, committed without malice. The entry enumerates the four Roman types, consistent with the civilian tradition.
Historical legal dictionaries are reliable on the Roman categories but tend to present the doctrine in its classical form without addressing how civilian jurisdictions adapted or generalized the principle in the nineteenth and twentieth centuries. The generalized fault principle — any negligent harm gives rise to an obligation — is more consequential for modern research than the four specific Roman categories, but it receives less attention in older dictionary sources.
Historical sources also do not address the comparative question of how quasi delict relates to common law negligence. Researchers making that comparison will need to go beyond the dictionary literature to civilian treatises or comparative tort scholarship.
Jurisdictional Note
Quasi delict is an operative legal category in Louisiana, Quebec, France, and other civil law or mixed jurisdictions. In common law jurisdictions it has no direct equivalent and is encountered primarily in comparative or historical contexts. Louisiana legal materials require particular attention because the state's tort law was shaped by this civilian framework and its codified provisions used the term until modernization of the Civil Code.
Encyclopedia Cross-Reference
Contracts — Classification (Bilateral, Unilateral, Express, Implied, Quasi-Contract), The Law Mind Contracts & Commercial Law Encyclopedia. The quasi-contract entry provides the civilian conceptual counterpart and explains the broader Roman taxonomy of obligations within which quasi delict is situated.