Definition
Latin: "He ought not to be burdened." A formal pleading phrase used in common law practice as the opening words of a defendant's plea, functioning as an equivalent to the more standard commencement formula *actionem non* ("he ought not to answer the action"). Where *actionem non* introduced a general denial or special plea in bar in personal actions, *onerari non debet* served the same structural purpose in certain specific actions — most notably in actions of debt on a bond or specialty, where the defendant pleaded that he ought not to be charged or burdened with the obligation alleged.
The phrase was not a universal substitute for *actionem non* but appeared in a narrow class of cases where the nature of the action made "burdened" a more apt characterization than "answering an action." In practice, the choice between the two commencement forms tracked the type of claim: *actionem non* for trespass and personal actions generally; *onerari non debet* where the plaintiff sought to impose a charge, debt, or liability on the defendant.
Common Confusion
*Onerari non debet* is easily conflated with *actionem non*, and the two phrases do overlap in function — both open a defendant's traversing plea. The distinction is contextual rather than substantive: *actionem non* denies the right to bring the action; *onerari non debet* denies the right to impose the burden or charge. Researchers encountering either phrase in historical pleadings should check the type of action before assuming equivalence. The related phrase *oneratur nisi* (he is charged unless) appears in a distinct procedural posture and should not be confused with either.
Why It Matters in Research
This term is primarily a historical pleading artifact. Researchers will encounter it in pre-reform common law records — English and early American — particularly in actions of debt, covenant, or on specialty instruments. After the procedural reforms of the nineteenth century (the English Common Law Procedure Acts beginning in 1852, and the eventual adoption of code pleading in American jurisdictions), formal commencement phrases like *onerari non debet* and *actionem non* disappeared from practice. They survive in case reports, plea rolls, and treatises from the sixteenth through early nineteenth centuries.
The key research trap is treating *onerari non debet* as a substantive defense rather than a formulaic pleading commencement. It signals the structure of the plea that follows; the actual legal argument is in the body of the plea, not in the opening phrase. Misreading the phrase as itself constituting a defense will mislead analysis of what was actually being contested.
For researchers working in early American records, awareness of which commencement formula was used can help identify the type of action underlying a fragmentary document when the writ or declaration is lost. The appearance of *onerari non debet* points toward a debt or charge-based action rather than a tort claim.
The Rapalje & Lawrence entry cross-references 1 Saunders 290, n. (b) — a reference to William Saunders's *Reports* (the annotated edition), a standard common law pleading authority. Researchers consulting that note will find the authoritative treatment of when this commencement was proper and when *actionem non* was required instead.
Historical Dictionary Support
Rapalje & Lawrence is the only shelf source providing a definition, and their entry is brief but accurate. They correctly identify *onerari non debet* as a pleading commencement used "in some few cases" as a substitute for *actionem non*, and they properly flag that the usage was limited rather than general. The cross-reference to 1 Saunders 290, n. (b) is the most useful pointer in the entry — Saunders's annotated reports were a primary authority on common law pleading forms, and the note at that location addresses exactly when each commencement formula was appropriate.
No other Law Mind shelf sources define this term independently. That absence itself reflects the phrase's status: it was a technical pleading formula known to practitioners through manuals and precedent books rather than a doctrinal concept demanding extended definition. Historical sources on common law pleading — Chitty's *Pleading*, Stephen's *Principles of Pleading*, and Gould's *Treatise on the Principles of Pleading* — address the broader category of plea commencements without always distinguishing this specific phrase by name.