Definition
A Latin term used in legal maxims and compound legal phrases meaning "no," "no person," or "nothing." Nullus does not function as a standalone legal doctrine but operates as a foundational word element in a family of maxims and compound terms that appear throughout common law pleading, evidence, and property. Its significance lies almost entirely in the phrases it anchors rather than in any independent legal meaning.
The two maxims most directly associated with nullus in legal practice are:
1. Nullus commodum capere potest de injuria sua propria — "No man can take advantage of his own wrong." A foundational principle of equity and common law preventing a party from benefiting from their own wrongful act. This maxim operates across contract, tort, property, and procedural contexts.
2. Nullus idoneus testis in re sua intelligitur — "No person is understood to be a competent witness in his own cause." A rule of testimonial competency rooted in Roman law and carried forward into early common law evidence doctrine, though substantially modified by modern competency statutes.
Common Language
Modern common usage (Wiktionary): Nullus has no standard entry in modern English usage. It is a Latin adjective with no anglicized form in contemporary general use.
Historical common usage (Webster's 1913): Not listed as an English word. Recognized only as a Latin element appearing in legal and scholarly compounds.
Editorial note: Because nullus carries no independent meaning in ordinary English, the COMMON LANGUAGE section is noted here only to confirm its absence from common usage. Researchers encountering nullus in historical documents should treat it as a Latin legal term requiring resolution through the specific phrase in which it appears, not through general dictionary resources.
Common Confusion
Nullus is sometimes loosely grouped with null and void or with the concept of nullity as though it were equivalent. It is not. Null, as an anglicized legal term, describes the legal status of an instrument or act — rendering it without effect. Nullus, by contrast, is a Latin qualifier meaning "no" or "no person," appearing in maxims that state legal principles rather than describe legal status. The two concepts are etymologically related but functionally distinct in research contexts. Conflating them risks misreading historical pleadings or maxim-based arguments.
Why It Matters in Research
Researchers encounter nullus primarily in one of three ways: in Latin maxims cited as authority in older judicial opinions and treatises, in compound terms appearing in historical pleading records, and as a cross-reference anchor in historical law dictionaries.
The principal research trap is treating nullus as a term of art with independent doctrinal content. It has none. Its value is entirely derivative — a researcher who finds nullus in a historical source must identify the complete phrase to understand the legal point being made. Anderson's dictionary handles nullus almost entirely by cross-reference, which is the correct instinct: nulla bona, nullius filius, nullum tempus, and related compounds each carry their own substantive doctrinal histories and warrant individual research.
The maxim nullus commodum capere potest de injuria sua propria has particular staying power. Coke's Institutes cite it, Broom's Legal Maxims treat it at length, and it appears in American equity decisions well into the nineteenth and twentieth centuries. Researchers working in equity, estoppel, or unjust enrichment contexts will encounter it in both its full Latin form and paraphrased English versions. The two forms may not always be cross-indexed in older digests.
The testimonial competency maxim — nullus idoneus testis in re sua — is primarily of historical interest. It reflects the pre-reform common law rule excluding interested parties from testifying. Evidence reform statutes in most common law jurisdictions abolished competency disqualifications based on interest in the nineteenth century, making this maxim largely obsolete in modern practice. Researchers in legal history, however, will find it cited in pre-reform evidence treatises and judicial opinions as controlling authority.
Corpus researchers should also note that nullus appears as a silent structural element in compound terms that have their own dictionary entries. When searching historical legal texts for any of the compound terms listed under Related Terms below, awareness of nullus as the negative quantifier in those phrases aids in recognizing variant Latin spellings and grammatical forms across manuscripts and printed reports.
Historical Dictionary Support
Anderson and Burrill handle nullus consistently as a Latin-only term with no independent English legal definition, directing readers to compound entries. This is the correct approach and reflects the term's function in the corpus.
Burrill provides more substantive content by quoting two maxims in full and supplying source references — Coke on Littleton at 148b for the wrongful advantage maxim, and the Digest at 22.5.10 for the testimonial competency maxim. These are genuine primary sources and remain reliable reference points for dating the doctrines. Burrill also cross-references Story's circuit court opinion reported in Sumner's Reports, which applied the competency maxim in an American federal context, demonstrating the maxim's continued judicial use in the early nineteenth century.
Anderson's entry is thinner, functioning almost entirely as a navigation device to other entries. It adds no independent authority but confirms the standard compound terms associated with nullus in the American legal dictionary tradition.
Neither source treats the wrongful advantage maxim with the depth it historically received in Broom's Legal Maxims, which gives that principle extended treatment including examples and qualifications. Researchers should not rely on Anderson or Burrill alone for the substantive content of that maxim.