Definition
An adjective describing conduct, intent, or an act that has the character or quality of a felony — that is, done with the deliberate purpose to commit a crime of felonious grade. In criminal pleading and statutory drafting, "felonious" historically served two related but distinct functions: (1) as a term of art in indictments signaling that the charged act was a felony rather than a misdemeanor, and (2) as a description of the mental state accompanying the act — an intent to commit a crime. A killing committed "feloniously" is one done with the criminal intent that elevates the act beyond accident or negligence. An assault committed "feloniously" is one that, if completed, would constitute a felony.
The term carries meaningful weight in older pleading practice. At common law, the word "feloniously" was required in the body of an indictment charging a felony offense. Omitting it could be fatal to the indictment. Modern procedural rules in most jurisdictions have abolished this technical requirement, but the word persists in statutes, jury instructions, and judicial opinions.
Common Language
Modern common usage (Wiktionary): Of, relating to, being, or having the quality of felony; done with intent to commit a crime.
Historical common usage (Webster's 1913): Having the quality of felony; malignant; malicious; villainous; traitorous; perfidious; in a legal sense, done with intent to commit a crime.
The common and legal meanings are close but not identical in one important respect. Ordinary language treats "felonious" as roughly synonymous with "villainous" or "wicked" — a general moral condemnation. The legal meaning is more precise: it designates a specific category of criminal intent tied to the grade of the offense, not merely moral turpitude. A researcher encountering "felonious" in a non-legal text should not assume the author intends any technical distinction about offense classification.
Common Confusion
"Felonious" is sometimes used interchangeably with "criminal" or "malicious" in both historical sources and popular writing. This conflation matters. Burrill notes explicitly that the popular usage — meaning simply "criminal" — is less precise than the technical meaning and that even some Ohio courts found the word "vague and indefinite" when compared against a modern criminal code. Researchers should not treat "felonious" as a reliable synonym for "malicious" in the mens rea sense; malice and felonious intent overlap but are not co-extensive. Similarly, "felonious" should not be confused with "infamous," which carries its own distinct legal consequences regarding competency to testify and civil disabilities.
Why It Matters in Research
Pleading requirements are the central trap. Pre-twentieth-century indictments routinely required the word "feloniously" as a term of art, and appellate records are full of cases turning on whether its omission or misspelling was reversible error. When reading historical case law, do not assume that the presence of "feloniously" in an indictment tells you much about intent doctrine — it may be purely formulaic. Conversely, its absence may signal a misdemeanor charge or a defective pleading, not an intentional drafting choice about mental state.
Jurisdictional codification creates further variation. As American states enacted criminal codes through the nineteenth century, many replaced common law felony categories with statutory classifications. In those jurisdictions, "felonious" became less technically meaningful and more adverbial — a word that colored the act charged without doing independent legal work. Burrill's observation about Ohio is the clearest example: once a state reorganizes its criminal law around a code, the common law term loses precision. A researcher working across jurisdictions must determine whether the source jurisdiction had codified its criminal law at the time the document was written.
For corpus research, "felonious" appears with high frequency in three distinct contexts: (1) indictment boilerplate, where it is essentially ceremonial; (2) jury instruction language, where it does carry substantive content about required intent; and (3) statutory definitions of aggravated offenses, where "felonious" modifies a noun (felonious assault, felonious homicide) to designate a specific offense grade. These three uses require different interpretive approaches and should not be collapsed.
Researchers working on felony murder, aggravated assault, or disenfranchisement questions will encounter "felonious" as a threshold term — whether the predicate act was "felonious" often determines whether enhanced consequences attach.
Historical Dictionary Support
The three source dictionaries converge on the core definition — done with intent to commit a crime, having the quality of felony — but diverge usefully on emphasis and application.
Burrill is the most candid about the term's instability. He distinguishes the technical meaning from the "popular" meaning and quotes an Ohio court's criticism that the word had become "vague and indefinite" under codified criminal law. This is the most practically useful observation in the historical record for modern researchers: the term's precision is inversely related to how thoroughly a jurisdiction had codified its criminal law by the time of any given source.
Bouvier emphasizes the intentional dimension — "done with deliberate purpose to commit a crime" — and aligns the term closely with the mental state element rather than the grade of offense. His definition imports language of moral condemnation ("malignant," "malicious," "villainous," "perfidious") that reflects the pre-code era's tendency to fuse moral and legal categories.
Black's (2nd Ed.) follows Bouvier's framing but adds a brief sub-entry for "felonious assault," which clarifies that the term operates on the grade of offense as well as the intent: a felonious assault is one that, if completed, would itself be a felony. This structural definition is more useful for modern analysis than the general moral language.
None of the historical dictionaries gives adequate treatment to the word's role as pleading boilerplate, which was its most routine function in practice. Researchers should supplement these entries with treatise material on criminal pleading — particularly on the technical requirements of common law indictments — to understand how frequently "felonious" appeared without carrying genuine doctrinal weight.
Jurisdictional Note
At common law and in jurisdictions following common law pleading, "feloniously" was a required term in felony indictments. Most American jurisdictions have abrogated this requirement by rule or statute, but the word survives in codified offense definitions, particularly for aggravated offenses. In states with early criminal codes (Ohio being the historical example), the word's technical precision eroded earlier than in states that retained common law pleading forms into the twentieth century.
Encyclopedia Cross-Reference
Homicide — Felony Murder Rule (The Law Mind Criminal Law Encyclopedia): For the application of "felonious" as a predicate element in felony murder doctrine.
Felony Disenfranchisement and Restoration of Rights (The Law Mind Criminal Law Encyclopedia): For the downstream consequences of felony classification to which "felonious" conduct gives rise.
DUI — Aggravated and Felony DUI (The Law Mind Criminal Law Encyclopedia): For a modern statutory context in which "felonious" grade is determined by aggravating factors.