Definition
De dolo malo is a Latin phrase meaning "of or founded upon fraud." It describes actions, pleas, or proceedings grounded in deceit or fraudulent conduct. The phrase appears most commonly as a qualifier in Roman-derived civil procedure, designating that a legal remedy or action has fraud as its essential basis. It is closely associated with the actio de dolo malo, the Roman law action available to a party who suffered harm through another's deliberate deceit, where no other adequate remedy existed.
Common Confusion
De dolo malo is sometimes loosely treated as synonymous with dolus malus (bad faith or evil intent generally), but the phrases carry distinct functions. Dolus malus denotes the mental quality — the deliberate, bad-faith intent to deceive. De dolo malo is a procedural and pleading designation — it identifies a cause of action or exception as being founded upon that fraudulent intent. A researcher encountering dolus malus in a philosophical or civilian context and de dolo malo in a procedural context is reading about related but functionally different things.
Why It Matters in Research
Researchers working in Roman law sources, early common law equity materials, or comparative private law will encounter de dolo malo as a term of art anchored in classical Roman civil procedure. Its appearance typically signals one of two things: the actio de dolo malo, the praetorian remedy against fraud codified in Digest 4.3, or the exceptio doli, a defensive plea asserting that the opposing party's claim is tainted by fraud.
In English legal sources, the phrase appears primarily in equity and civilian-influenced texts rather than common law pleading. Chancery materials from the sixteenth through eighteenth centuries may invoke de dolo malo reasoning without naming it directly, instead framing relief in terms of conscience and unconscionable conduct — the functional English equivalent. Researchers should not expect to find the Latin phrase itself in standard common law pleading records; its natural habitat is treatise literature, equity jurisprudence, and sources drawing on the civil law tradition.
The phrase also surfaces in Scottish law, mixed civil/common law jurisdictions, and Louisiana materials, where the civilian heritage makes direct use of the Roman terminology more likely. A researcher moving between English equity sources and Scottish or Louisiana authorities should be alert to the fact that de dolo malo carries more technical precision and more explicit procedural weight in those civilian systems than in English equity, where fraud doctrine was developed largely in parallel without consistent use of the Roman label.
One indexing trap: early digests and abridgments sometimes list de dolo malo as a subentry under actio or under dolo, not as a standalone term. Burrill's entry, for instance, runs de dolo malo directly into an unrelated entry (de domo reparanda) without clear visual separation, a typographical pattern common in compressed legal dictionary formats of that era. Researchers consulting scanned or OCR-processed versions of Burrill should verify they are reading the correct entry.
Historical Dictionary Support
Black's Law Dictionary (both first and second editions) defines de dolo malo identically and minimally: "of or founded upon fraud," with a citation to Digest 4.3 and a cross-reference to actio de dolo malo. Burrill's Law Dictionary gives the same substantive content but in a compressed format that bleeds into the next entry, reflecting the space constraints of mid-nineteenth-century legal lexicography. None of the three source dictionaries expand beyond the phrase's literal meaning or its Digest citation.
What the historical dictionaries do not provide is any account of how de dolo malo reasoning was absorbed, translated, or displaced in English equity practice. The silence is instructive: by the time these dictionaries were compiled, English lawyers had largely worked out fraud doctrine through equity without sustained recourse to the Roman formula. The phrase persisted in learned treatises and comparative contexts, but the historical dictionaries treat it as a term of art requiring no elaboration for their intended audience — an assumption that makes the entries less useful for a researcher without a civilian background.
Encyclopedia Cross-Reference
See Law Mind Encyclopedia: Fraud (Civil Law Origins); Actio de Dolo Malo; Roman Law in English Equity