Definition
A delator (Latin) is an accuser, informer, or denouncer — a person who formally accused or reported another to public authorities. The term originates in Roman civil law, where delators played a formal institutional role in bringing accusations before the state, often in exchange for a portion of any resulting fine or confiscated property.
In modern legal usage, the term is largely historical and appears almost exclusively in civil law scholarship, Roman law contexts, and older Anglo-American legal literature. It is not a working term in contemporary common law practice.
Common Language
Modern common usage (Wiktionary): An accuser; an informer.
Historical common usage (Webster's 1913): An accuser; an informer. [Rare.]
The common and legal definitions are nearly identical in surface meaning, but the legal context adds institutional weight. In Roman law, a delator was not merely an informant in the colloquial sense but a participant in a formal prosecutorial mechanism, often professionally motivated by financial reward. The common definition strips this institutional dimension entirely.
Common Confusion
Delator is sometimes loosely treated as synonymous with the common law informer or qui tam relator. These are related but distinct roles. The qui tam relator in English and American law shares the delator's financial incentive structure — bringing suit on behalf of the state in exchange for a share of the recovery — but operates through a defined statutory mechanism. The Roman delator functioned under a different procedural system and carried broader, sometimes more politically charged, connotations, particularly under the late Republic and Empire, when delation became associated with politically motivated prosecutions. Researchers moving between civil law and common law sources should not treat these terms as interchangeable.
Why It Matters in Research
Researchers encountering delator in primary or secondary sources should pay close attention to period and legal tradition.
In Roman law sources and treatises drawing on civil law, delator describes a specific procedural actor with defined rights and incentives. The term appears in Justinian's Codex (Cod. 10.11) in connection with rules governing informers — their privileges, their share of forfeitures, and restrictions on their conduct. Any reading of these provisions requires understanding that the delator was not a peripheral figure but an engine of enforcement in Roman fiscal and criminal law.
In English legal literature, the term surfaces in discussions of Roman procedure, in historical treatments of informers and penal statutes, and occasionally in ecclesiastical law contexts. It does not appear as an operative term in common law pleading or procedure.
The pejorative connotation — the sycophant gloss preserved in both editions of Black's — reflects the historical reputation of professional delators, particularly those who exploited the system for personal gain under the Roman Empire. When Black's (1st and 2nd editions) include "sycophant" alongside the neutral "informer," they are registering this cultural and historical freight, not a separate legal meaning. Researchers should not read "sycophant" as a technical legal element.
For corpus researchers working in Law Mind: the term will appear most frequently in civil law treatises, Roman law scholarship, and historical surveys of prosecutorial systems. It is unlikely to appear in case law or statutory material except in direct quotation of Latin sources or academic commentary.
Historical Dictionary Support
The four source dictionaries are in close agreement. All define delator as an accuser or informer. Burrill adds the most legal-historical depth, citing Justinian's Codex, Calvin's Lexicon, and Brissonius — establishing the term's grounding in Roman civil law procedure and providing the researcher with a trail into primary sources. Bouvier cites Du Cange, pointing toward the medieval Latin tradition, which suggests the term persisted beyond classical Roman law into medieval ecclesiastical and civil law usage.
Black's (both editions) append "sycophant" to the definition, a characterization the other dictionaries omit. This is not a technical legal meaning but a value judgment embedded in the definition — a signal that by the time these dictionaries were compiled, the delator's historical reputation for abuse had become part of how Anglo-American legal writers understood the term. Researchers should treat this gloss as interpretive commentary, not definitional content.
None of the historical dictionaries address the qui tam parallel or distinguish the delator from the common law informer — a gap that can mislead researchers working across legal traditions.
Jurisdictional Note
Delator is not a term of art in any U.S. or English common law jurisdiction. It appears in civilian legal systems and Roman law scholarship. Researchers working in Louisiana, Quebec, or other mixed civil law jurisdictions may encounter it in historical materials, but even there it is not current operational terminology.