Definition
Improper, unlawful, or wrongful conduct. In law, misbehavior carries specific operative weight in at least three distinct contexts:
1. Official or fiduciary misbehavior. Fraudulent dealing by a person entrusted with property or authority — including bankers, factors, agents, trustees, corporate directors, and public officers — who misapplies money, goods, or securities placed in their care. In this sense, misbehavior overlaps with criminal breach of trust and is a predicate for both civil liability and criminal prosecution.
2. Juror misbehavior. Improper conduct by a juror or jury during trial or deliberations that may constitute grounds for a new trial or for setting aside a verdict. Courts have long recognized that jury integrity is foundational to the verdict's validity, and misbehavior — ranging from unauthorized communications to exposure to extraneous evidence — can vitiate a jury's findings.
3. Judicial and officer conduct. In constitutional and administrative usage, misbehavior is a standard governing tenure of public officers, judges, and certain appointed officials. Officers who hold their positions "during good behavior" may be removed upon a finding of misbehavior, a standard distinct from impeachable offenses in some frameworks.
Common Language
Modern common usage (Wiktionary): Action or conduct that is inappropriate, improper, incorrect, or unexpected.
Historical common usage (Webster's 1913): Improper, rude, or uncivil behavior; ill conduct.
The everyday sense of misbehavior — rudeness, impoliteness, a child acting out — is purely social and carries no legal consequence. Legal misbehavior is narrower and outcome-determinative: it triggers specific remedies (new trial, removal from office, criminal liability) rather than mere social disapproval. A researcher encountering the word in a legal source should not read it as a mild descriptor; it is a term of art invoking a defined category of actionable wrong.
Common Confusion
Misbehavior, misconduct, and malfeasance are often used interchangeably in casual legal writing but are not synonymous. Misconduct is the broader modern standard, particularly in professional discipline and employment law. Malfeasance denotes wrongful acts committed in the performance of official duties and is narrower than misbehavior in its official-conduct sense. Misbehavior in the juror context is its own doctrinal category and does not map cleanly onto either misconduct or malfeasance. Researchers should not substitute these terms when reading historical sources, where the choice of word may signal a specific legal framework.
Why It Matters in Research
Misbehavior is a chameleon term in the corpus: the same word does different legal work depending on context, and historical sources rarely signal which sense they intend. A researcher must identify the actor (juror, trustee, judge, public officer) before the term's doctrinal meaning becomes clear.
The juror misbehavior doctrine is heavily represented in 19th-century New York and Tennessee case law and is the sense most commonly discussed in early appellate opinions. Researchers tracing new trial doctrine will find misbehavior cited as a standalone ground alongside inadequate damages and newly discovered evidence — treat it as a procedural term of art in that context.
The fiduciary and official misbehavior sense connects to the 19th-century development of breach of trust as a criminal category. Stephen's Criminal Digest (cited in Black's) is the key treatise bridge between English and American formulations. American codifications often absorbed this concept under embezzlement or fraudulent conversion statutes, so later sources may not use misbehavior at all for the same conduct.
The constitutional tenure sense — officers holding office "during good behavior" and removable for misbehavior — appears in early state constitutions, federal judicial tenure discussions, and debates over Article III. This usage is sparse in standard legal dictionaries but significant in constitutional history research.
Anderson's bare cross-reference to BEHAVIOR is unhelpful; researchers should not rely on Anderson alone for this term.
Historical Dictionary Support
Black's (1st and 2nd editions) present two separate entries for misbehavior without formally distinguishing them by subsection: one treating the fiduciary/criminal sense (citing Stephen's Criminal Digest and Sweet's Law Dictionary), the other treating the general and juror-misbehavior sense. The 2nd edition adds case citations for the juror context that the 1st edition omits, making it the more useful research tool for that doctrine.
Bouvier adds the important point that a party guilty of misbehavior — such as threatening another — may be bound to good behavior by a court, connecting misbehavior to the ancient surety-of-the-peace tradition. This preventive-justice dimension is absent from Black's and is easy to overlook.
Anderson's cross-reference to BEHAVIOR without elaboration is a gap: researchers should not expect Anderson to illuminate this term's doctrinal content.
None of the historical dictionaries adequately treats the constitutional tenure sense. That dimension must be pursued through primary constitutional sources and treatises on judicial and executive power rather than through the standard legal dictionaries.
Jurisdictional Note
The juror misbehavior doctrine varies by jurisdiction in its procedural requirements: some states require a showing of actual prejudice; others treat certain categories of juror misbehavior as presumptively prejudicial. The fiduciary misbehavior sense has largely been absorbed into statutory embezzlement and breach of fiduciary duty frameworks, which differ materially across states.