Definition
A Latin adjective used in civil law and early English legal writing to mean illicit, unlawful, illegitimate, spurious, false, or forged. The term functions descriptively rather than as an independent legal concept — it qualifies a noun to indicate that the thing so described is counterfeit, unauthorized, or otherwise lacking legal validity.
The word appears most commonly in compound phrases:
1. Adulterina moneta — counterfeit or debased coin; money unlawfully fabricated outside the authority of the sovereign mint.
2. Adulterinum testamentum — a forged will; a testamentary document falsified in whole or in part.
3. Sigillum adulterinum — a spurious or counterfeit seal; a seal affixed without authority or fabricated to deceive.
4. Applied more broadly to any instrument, grant, or legal act that is unauthorized, corrupt, or fabricated outside lawful authority.
Common Confusion
ADULTERINUS should not be confused with terms derived from adultery (adulterium) in the sense of marital infidelity, though both share a Latin root. In legal Latin, adulterinus carries the dominant sense of falsification and illegitimacy — the corruption of something that should be genuine — rather than sexual misconduct. Researchers encountering the term in medieval or civil law sources should resist the instinct to read it as a reference to illegitimate birth or to the law of adultery unless the surrounding context makes that meaning explicit. The overlap is linguistic, not legal.
Why It Matters in Research
ADULTERINUS is a term of art in Latin legal texts and will appear primarily in civil law sources, their English translations, and early English legal treatises drawing on Roman or civilian authority. Several research considerations apply.
First, the term is compound-dependent. It carries almost no independent legal weight standing alone; its meaning is determined by the noun it modifies. Researchers searching a corpus for adulterinus should expect to find it attached to moneta, testamentum, sigillum, or similar nouns, and should index accordingly.
Second, the term bridges Roman civil law and early English law. Burrill cites both the Digest (Justinian's Digesta) and Fleta, a late thirteenth-century English legal treatise. This dual provenance means the term may appear in sources that are nominally English but are drawing directly on civilian doctrine. Researchers should not assume that an appearance in an English-language source reflects native common law usage — it may instead signal the author's reliance on Roman or canon law materials.
Third, the concept captured by adulterinus — the legal invalidation of instruments because they are false or unauthorized — connects to a broader cluster of offenses in both Roman and English law: forgery, coinage offenses, and the fraudulent use of seals. In English legal history, the fraudulent use of a seal (sigillum adulterinum) was a serious matter with both civil and criminal consequences, particularly in an era when sealed instruments were the primary mode of authenticated legal transactions.
Fourth, the Burrill entry appears to be truncated, ending mid-sentence with "Unlawful; unauthorized; i —." Researchers relying on Burrill for this term should treat the entry as incomplete and seek supplementation from other civilian glossaries or the primary sources Burrill cites.
Historical Dictionary Support
Burrill's Law Dictionary is the sole source in the Law Mind shelf for this term, and its entry is reliable as far as it goes. Burrill correctly identifies the civil law provenance, correctly separates the Roman and early English usages, and provides specific citations to the Digest and to Fleta. The citations to the Digest (48.13.6.1 on counterfeit money and 48.10.6 on forged wills) point to the title De falsa moneta and the title De lege Cornelia de falsis respectively — both genuine titles dealing with the Lex Cornelia de Falsis, the Roman law on forgery and falsification. The Fleta citations (lib. 3, c. 14, § 4 and lib. 4, c. 10, § 3) relate to the use of seals in English legal practice, consistent with the period in which Fleta was composed.
What Burrill does not provide — likely because the entry is truncated — is any treatment of the unauthorized guild or trade use of adulterinus, which in some civilian contexts referred to goods produced outside the lawful guild structure. That usage appears in other civilian glossaries and is worth noting when the term appears in commercial or mercantile legal sources.
No other Law Mind shelf dictionaries currently carry this term. Thomas Blount's Nomo-Lexicon and other historical English law dictionaries would be natural supplements if available.
Jurisdictional Note
ADULTERINUS is a civil law term and has no significant common law life as an independent term of art. Its appearances in English legal texts are almost exclusively in sources with civilian influence — Fleta, Bracton, and works drawing on Roman authority. Researchers working in common law jurisdictions after the seventeenth century will rarely encounter the term outside historical or comparative law contexts.