Definition
In historical Scots law and early English legal usage, *fou* is a term meaning mad, insane, or mentally incapacitated — used to describe a person lacking the mental capacity required to enter into legally binding acts or to be held to ordinary legal responsibility. The term appears in older Scottish legal records and pleadings as a descriptor of mental incompetence analogous to the Latin *furiosus* or the English "lunatic."
Common Language
Modern common usage (Wiktionary): Drunk.
Historical common usage: The word *fou* in ordinary Scottish dialect means drunk or intoxicated — full to the point of inebriation.
The gap here is significant and practically important. In common Scottish usage, *fou* describes a temporary state of intoxication. In legal contexts, the term was applied to permanent or recurring mental incapacity — closer to what modern law would call incompetence or insanity. A researcher encountering *fou* in a historical Scottish legal document should not assume it refers to drunkenness. The legal meaning describes a condition affecting legal standing, not a transient state.
Common Confusion
*Fou* is frequently confused with *foribundus* or *furiosus* in transcription and in later editorial commentary. Burrill's Law Dictionary notes that the word is repeatedly misprinted as *fotibellus* or *fotianellus* in Fleta and related sources, indicating early copyist errors that have propagated into later legal literature. Researchers relying on manuscript sources or early printed editions should treat variant spellings with suspicion and verify against parallel texts.
Why It Matters in Research
The primary research trap with *fou* is its appearance in historical Scottish and Anglo-Norman records where misprints and spelling variants obscure meaning. Burrill flags the misprinting problem directly, noting the word repeatedly appears corrupted in Fleta. Any researcher working with Fleta (the 13th-century English legal treatise) or with early Scottish pleadings should be alert to garbled forms of this term.
The word bridges Scots vernacular and legal Latin traditions. Where Latin sources would use *furiosus* or *non compos mentis*, Scots practice sometimes substituted *fou* or cognate forms. This matters when tracing incapacity doctrine across jurisdictions or time periods: the underlying legal concept may be continuous even when the vocabulary shifts between Latin, Scots, and later English terminology.
Researchers constructing arguments about historical mental incapacity doctrine — especially in the context of contract voidability, testamentary capacity, or criminal responsibility in Scottish or northern English records — should flag *fou* as a technical term of art and not treat it as mere vernacular color.
Historical Dictionary Support
Burrill's Law Dictionary is the primary source for *fou* in the common law dictionary tradition, and even Burrill's treatment is thin — the word appears in the context of a broader passage about jurisdictions for various pleas, with the misprinting note serving as the most substantive editorial contribution. The passage from Fleta cited by Burrill (lib. 2, c. 12, § 1) places *fou* in a procedural context: determinations involving persons of this description were to be made before the justices of assize, with certain pleas reserved for the Court of Common Bench.
What the historical dictionaries do not address is the overlap between *fou* as a Scots legal term and the broader civilian and canon law traditions dealing with mental incapacity. The Roman law *furiosus*, the canonical *amens*, and the common law *non compos mentis* are treated extensively in other sources, but *fou* sits at the vernacular edge of legal vocabulary and receives little systematic treatment in any of the standard historical dictionaries. Researchers should not expect to find it indexed in Bouvier, Black (early editions), or Tomlin's Law Dictionary without careful searching.
Jurisdictional Note
*Fou* as a legal term of art is principally encountered in Scottish legal sources and in English legal texts influenced by Scottish or northern practice. Its appearance in Fleta suggests some early penetration into English common law writing, but it did not become standard English legal vocabulary. Modern Scots law has replaced it entirely with statutory and common law terminology for incapacity.