Definition
In Roman and civil law, a sicarius (plural: sicarii) is an assassin or would-be killer — specifically, a person who carried a concealed dagger, knife, or other weapon with the intent to commit murder. The term derives from sica, the short curved blade characteristically associated with such persons. A sicarius was not merely someone who committed homicide but one who armed himself with lethal intent, making the carrying of the weapon itself an element of the offense.
The term appears in Roman law principally through the Lex Cornelia de sicariis et veneficis, a statute of the dictator Sulla (circa 81 BCE) that established criminal liability for assassins and poisoners. Under this law, a person could be prosecuted not only for completed killing but for going about armed with murderous intent — a significant early example of inchoate criminal liability in Western legal history.
Common Language
Modern common usage (Wiktionary): Any of a group of Jews who attempted to expel the Romans from Judea using concealed daggers.
Historical common usage: The historical common usage tracks closely with the legal term — a hired assassin or dagger-man, derived from the same Roman root.
Editorial note: The Wiktionary definition reflects a historically specific usage — the Sicarii were a first-century CE Jewish resistance movement whose name was drawn directly from this Roman legal term. The legal meaning is broader and older: any person who carries a concealed blade with homicidal intent, not limited to this particular group. Researchers encountering the term in legal sources should not assume the sectarian or historical-movement meaning; the civil law usage is categorical and definitional, not referential.
Why It Matters in Research
Sicarius appears almost exclusively in sources dealing with Roman law and the reception of civil law into later European legal systems. Researchers working in the Law Mind corpus should note several navigational points.
First, the term's primary legal home is Justinian's Digest (Digest 48.8) and the Institutes (Inst. 4.18.5), both of which address the Lex Cornelia de sicariis. Any Law Mind source that cites or discusses these texts — treatises on Roman criminal law, commentaries on the civil law tradition, or comparative criminal law works — may use sicarius as technical vocabulary without definition, assuming reader familiarity.
Second, the term illustrates an early doctrinal move that echoes forward into common law: punishing armed intent separately from completed harm. Researchers tracing the history of inchoate offenses, attempted murder, or carrying concealed weapons statutes may find the Roman treatment of sicarius useful as background jurisprudence, even if the direct line of influence runs through continental rather than English sources.
Third, Burrill's entry places sicarius immediately adjacent to sich/sichet (a water furrow), a reminder that Latin legal terms in historical dictionaries are alphabetically proximate to unrelated terms. Researchers scanning historical dictionaries should be careful not to conflate entries that appear in sequence but have no legal relationship.
Historical Dictionary Support
Burrill's Law Dictionary provides a compact but accurate entry: a sicarius is an assassin who carried a knife or dagger with intent to kill, grounded in the Institutes and Digest citations. Burrill correctly identifies the Lex Cornelia de sicariis as the operative statute and points researchers to the relevant civil law sources.
What Burrill's entry does not develop is the broader significance of the Lex Cornelia as a criminal law instrument — it was among the first Roman laws to systematize categories of serious crime (the leges Corneliae collectively), and the de sicariis provision was notable for extending liability to the intent to kill, not just the act. Burrill treats sicarius as a vocabulary item rather than a doctrinal concept, which is appropriate for a dictionary but limits its usefulness as a starting point for substantive research.
No significant divergence appears across the historical sources for this term; the core meaning has remained stable. The absence of the term from common law dictionaries (such as Black's early editions) reflects the fact that sicarius never migrated meaningfully into English legal practice, remaining a civil law and Roman law term of art.
Jurisdictional Note
Sicarius is a term of Roman and civil law and does not appear as operative legal vocabulary in common law jurisdictions. It surfaces in legal scholarship, comparative law, and historical jurisprudence rather than in statutes, codes, or judicial opinions of any modern jurisdiction.