Definition
Vi aut clam is a Latin phrase from Roman civil law meaning "by force or covertly." It describes two distinct modes by which a possessor could wrongfully acquire or interfere with property in a manner that gave rise to an interdict under Roman law — specifically the interdictum quod vi aut clam under Digest 43.24.
Vi (by force) referred to acts done against the express prohibition of the possessor. A thing was considered done vi when a person proceeded despite being told not to — the prohibition itself made the act forcible in the legal sense, regardless of whether physical violence was involved.
Clam (covertly or clandestinely) referred to acts done secretly, by a person who had reason to believe the possessor would object and therefore concealed what they were doing to avoid that opposition. The clandestine nature substituted for open defiance: the actor evaded rather than overcame the possessor's will.
Together, the phrase captures two forms of wrongful interference with possession — one overt and defiant, one hidden and evasive — both treated as actionable under the Roman interdict system.
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Common Confusion
Vi aut clam is frequently grouped with the related phrase vi, clam, aut precario, which describes the three defective modes of possession in Roman law: by force, covertly, or by permission (precario). The distinction matters for research: vi aut clam as a standalone phrase typically refers to the specific interdict of Digest 43.24, which addressed wrongful work done on land. Vi, clam, aut precario appears more broadly in the context of possessory interdicts generally, including the uti possidetis and utrubi interdicts, where it described the grounds on which a possessor could be displaced. Conflating the two can lead a researcher to the wrong section of the Digest and the wrong line of secondary commentary.
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Why It Matters in Research
Researchers encounter vi aut clam primarily in three contexts: Roman law sources and their civilian descendants, English Chancery and common law treatment of possession and injunction doctrine, and modern property scholarship tracing the historical foundations of possessory protection.
The phrase appears almost exclusively in its Roman law context in Anglo-American legal dictionaries, and most entries — including Black's — do little more than translate the words and cite Digest 43.24. This brevity is a trap. The interdict quod vi aut clam was a substantive Roman remedy with technical requirements, and understanding how it was received (or rejected) in English equity requires going beyond the dictionary.
In historical common law sources, you may encounter vi aut clam cited in equity proceedings involving interference with land — particularly cases involving excavation, construction, or diversion of water — where Chancery courts occasionally drew on civilian learning to justify injunctive relief. The phrase does not translate directly into a recognized common law cause of action, so when it appears in English or early American cases, it is almost always as learned reference rather than operative legal doctrine.
For corpus researchers: the Digest citation (43.24) is consistent across all shelf sources and is reliable as a cross-reference point. The fuller Burrill entry is the most useful of the historical dictionaries for this term — it begins to unpack the substantive distinction between vi and clam in a way that Black's does not, and it preserves fragments of the original Latin text from the Digest that allow comparison with primary sources.
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Historical Dictionary Support
All three shelf sources agree on the core translation and cite Digest 43.24. Black's (both editions) provides only the bare translation and citation. Burrill goes further, quoting from the Digest to articulate the distinction between the two modes: vi factum describes an act done contrary to a possessor's prohibition; clam factum describes an act done by a person who concealed what they were doing because they anticipated objection. Burrill's entry, though incomplete as reproduced here, is the most substantively useful of the three.
None of the shelf sources addresses reception of the doctrine in English or American law, nor do they distinguish vi aut clam from the broader formula vi, clam, aut precario. This gap is significant for any researcher trying to connect Roman possessory doctrine to common law or equity developments. Secondary sources in Roman law and civilian tradition — rather than Anglo-American legal dictionaries — are the appropriate next stop after establishing the basic definition.
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Jurisdictional Note
Vi aut clam has no operative doctrinal life in contemporary American or English common law as a distinct cause of action or defense. Its relevance to common law jurisdictions is almost entirely historical and comparative. Civilian jurisdictions in the civil law tradition retain closer structural parallels to the Roman possessory interdict system, and researchers working in those systems will find the phrase more directly productive.
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