Definition
Guinis (also rendered as *de guinis*) is a Latin term of feudal property law meaning "on account of failure or deficiency of blood." It describes a ground on which title to land could be defeated or an interest extinguished when the bloodline of a grantee or tenant failed — that is, when the person died without heirs of the blood required to carry the estate forward. The term appears in the context of conditions and limitations attached to feudal grants, where continuation of the grant depended on the survival of lineal or blood descendants.
In older English law, *guinis* functioned as a technical descriptor for one species of defeasance: the extinguishment of a tenant's interest not by forfeiture or crime, but by the natural extinction of the qualifying line of descent.
Common Confusion
Bouvier pairs *guinis* with a companion term: *propter delictum* ("for or on account of crime"). The two terms represent distinct grounds for the same legal consequence — defeat of a property interest or disqualification from a right. *Guinis* operates through the accident of nature (no heirs); *propter delictum* operates through the moral fault of the individual. Researchers encountering either term in historical property or challenge contexts should confirm which ground is being invoked. The two are sometimes listed together in enumerations of disqualifying conditions, which can cause them to be read as synonyms when they are not.
Why It Matters in Research
This term will appear almost exclusively in pre-twentieth-century common law materials dealing with feudal tenures, fee tail estates, and the law of descent. Researchers working in those areas should note:
**Feudal tenure context.** *Guinis* is a relic of the feudal system, where grants were frequently conditional on the continuation of bloodlines. Its practical significance collapsed in England with the Statute of Wills (1540), the Tenures Abolition Act (1660), and the gradual dismantling of fee tail through common recovery and later statutory reform. By the time American jurisdictions were developing their own property law, *guinis* had little operational force, though it appears in treatises as historical explanation.
**Challenge context.** Bouvier cross-references CHALLENGE, indicating the term also appeared in jury law. A juror could historically be challenged *propter defectum* (for defect) — and deficiency of blood (guinis) was one such defect, as it could bear on questions of inheritance of status, alienage, or qualification. Researchers in historical trial practice should look for *guinis* in that procedural context as well as in the property context.
**Indexing traps.** Because *guinis* is a Latin term that appears inconsistently spelled and abbreviated in older digests and abridgments, full-text searches may miss instances where it is rendered in variant forms or paraphrased in English as "want of blood" or "failure of issue."
**Limited American footprint.** American legal dictionaries after Bouvier give this term little or no independent treatment, reflecting that fee tail and bloodline-conditioned grants never took deep root in most American jurisdictions. Researchers working in American sources after roughly 1850 are unlikely to encounter *guinis* outside of academic or comparative treatments.
Historical Dictionary Support
Bouvier's Law Dictionary provides the primary definition and does so with notable economy: "on account of failure or deficiency of blood," with a citation to Blackstone's *Commentaries*, Book II, chapter 245. This is consistent with Blackstone's treatment of the conditions under which estates could fail and the manner in which feudal grants were extinguished by want of heirs.
No other source dictionary in the Law Mind corpus provides an independent entry for *guinis*. The term does not appear in standard American legal dictionaries of the nineteenth or twentieth century as a stand-alone entry, suggesting it was already regarded as a historical term of art by the time American legal lexicography matured.
The pairing of *guinis* with *propter delictum* under Bouvier's CHALLENGE entry places the term in a taxonomy of legal disqualifications — a structure consistent with both Blackstone and the civilian tradition that informed early American legal education.