Definition
Departing from prescribed legal form, rule, or procedure in a way that renders an act, proceeding, or instrument defective but not necessarily void. A legal act is irregular when it fails to conform to the rules governing how it must be done, even if the underlying authority to do it exists.
In practice, "irregular" describes a spectrum of procedural and formal defects. Courts distinguish irregularity from invalidity: an irregular act may be voidable or subject to correction, while a void act has no legal effect from the outset. The distinction is consequential — an irregular judgment may be set aside on motion; a void judgment can be attacked collaterally at any time.
The term appears across multiple legal contexts:
1. Irregular procedure: A step in litigation or administrative process taken without strict compliance with applicable rules — wrong form, wrong timing, wrong notice — but within the court's or body's general jurisdiction.
2. Irregular process: A writ or summons that departs from required form. Historically distinguished from void process, which issued without authority entirely.
3. Irregular judgment: A judgment entered in a manner inconsistent with the applicable rules of practice, often because of defect in notice, form, or procedure preceding entry. Typically subject to direct attack or motion to vacate, not collateral attack.
4. Irregular indorsement: An indorsement on a negotiable instrument by a party not otherwise connected to the instrument — a stranger who signs on the face or back outside the ordinary chain — creating questions about the nature of the obligation assumed.
Common Language
Modern common usage (Wiktionary): Nonstandard; not conforming to rules or expectations; lacking symmetry, regularity, or uniformity.
Historical common usage (Webster's 1913): Not regular; not conforming to a law, method, or usage recognized as the general rule; not according to common form; not conformable to established principles; not normal; unsymmetrical; erratic.
The ordinary meaning — simply "not regular" — maps onto the legal meaning more closely than most legal terms, but the gap matters. In common usage, irregular carries no implication about consequences or remediability; something irregular might just be odd or unusual. In law, irregular is a term of art signaling a specific category of procedural defect that is curable or waivable, as opposed to a defect that is jurisdictional and therefore fatal. The researcher who reads "irregular" in a historical legal source and interprets it loosely as "flawed" or "defective" may miss the critical implication that the act or proceeding remained capable of producing legal effect unless timely challenged.
Common Confusion
IRREGULAR vs. VOID vs. ERRONEOUS: These three terms are frequently conflated in historical sources and even in judicial opinions, but they carry distinct meanings with different consequences.
— Void: The act has no legal existence; it may be attacked at any time, by anyone affected, including collaterally. No jurisdiction existed, or the defect goes to the root of authority.
— Irregular: The act was within jurisdiction but was done improperly. It may be set aside on direct attack but generally stands until challenged. Failure to timely object may constitute waiver.
— Erroneous: The act was within jurisdiction and validly done, but the court or officer reached an incorrect result. Erroneous acts are subject to correction on appeal, not by collateral attack or motion to vacate.
Anderson's Dictionary of Law cross-references "ERRONEOUS" and "REGULAR," signaling that these terms form an interlocking triad. Researchers should approach all three together when working through historical procedural materials.
Why It Matters in Research
The void/irregular/erroneous distinction is one of the most practically significant classification problems in historical procedural law, and the historical dictionaries are only partial guides. Black's defines irregular as departure from prescribed course; Bouvier and Burrill say "out of rule, not according to rule." None of the source dictionaries draws out the consequences of irregularity as explicitly as practice-focused treatises do.
Researchers working in 19th-century pleading and practice materials — code pleading states, chancery courts, or common law jurisdictions before procedural consolidation — will encounter "irregular" applied to judgments, writs, process, and indorsements with varying remedial implications depending on the jurisdiction and era. The consequences of irregularity shifted as states adopted Field Code procedure and later Federal Rules-style regimes, which broadened curative provisions and reduced the list of defects that would be treated as jurisdictional voids.
In equity practice particularly, the concept of irregular process had its own procedural vocabulary. Equity courts could treat defective service or irregular returns differently than courts of law.
Researchers tracing the irregular/void line in judgment enforcement should also watch for the canon that a party who appears and litigates without objecting to an irregularity may be held to have waived it — a rule that does not apply to void judgments. This waiver principle is deeply embedded in older case law and is not always legible from the dictionary definitions alone.
The term also appears in negotiable instruments law in the context of "irregular indorsers" — a usage that evolved with the law merchant and carries its own analytical weight distinct from the procedural meaning.
Historical Dictionary Support
The four source dictionaries converge on a single core meaning: departure from prescribed rule or form. Bouvier and Burrill are nearly identical — "out of rule; not according to rule" — and Burrill adds the Latin root (irregularis) as derivational context. Black's adds the useful qualifier "improper or insufficient, by reason of departure from the prescribed course," which signals the connection to formal requirements rather than substantive law. Anderson's is the least informative entry of the four, redirecting to ERRONEOUS and (presumably) REGULAR.
What all four sources omit is the crucial analytical function of the term: its role in a tripartite classification of defective legal acts. None of the historical dictionaries explains that irregular acts are neither void nor merely erroneous, and none describes the remedial consequences — that irregularity is subject to direct attack but not collateral attack, and that it can be waived. Researchers who rely solely on these dictionary definitions risk underestimating the term's operational significance in procedural doctrine.
The historical dictionaries reflect a 19th-century practice context in which courts were highly attentive to the form of writs, process, and judgments. Modern procedural reforms have absorbed or eliminated many of the specific irregularities those courts addressed, so older sources may describe categories of defect that no longer exist as discrete doctrinal problems.