Definition
To incur a liability is to have it fall upon one by operation of law or by one's own act or omission — not by voluntary contractual undertaking. In legal usage, the word carries a specific weight: liabilities are incurred; debts are contracted. The distinction matters because incurring implies an obligation that arises externally or consequentially, not from an affirmative agreement between parties.
In practical usage across contracts, taxation, and civil liability, "incur" now also appears more broadly to mean "to become subject to" costs, penalties, fees, or obligations as a result of some triggering event or conduct. Context determines whether the classical distinction from "contract" is operative.
Common Language
Modern common usage (Wiktionary): To bring upon oneself or expose oneself to, especially something inconvenient, harmful, or onerous; to become liable or subject to.
Historical common usage (Webster's 1913): To meet or fall in with, as something inconvenient, harmful, or onerous; to put one's self in the way of; to expose one's self to; to become liable or subject to; to bring down upon one's self; to encounter; to contract — as in, to incur debt, danger, displeasure.
Note: The ordinary and historical meanings treat "incur" as broadly synonymous with "contract" or "bring upon oneself," which flattens the distinction that legal usage carefully preserves. Webster's 1913 uses "to incur debt" as an illustrative phrase — precisely what the legal authorities say is wrong. That slippage is the research trap.
Common Confusion
INCUR vs. CONTRACT: In legal writing, these words are not interchangeable. One contracts a debt through affirmative, volitional agreement. One incurs a liability when the law imposes an obligation — by operation of statute, by conduct, by tort, or by some act whose legal consequence attaches without the party's explicit undertaking. Historical sources from Bouvier, Anderson, and both editions of Black's are unanimous on this point. Modern commercial drafting has eroded the precision of this distinction, with "incurred costs" and "incurred expenses" now appearing routinely as near-synonyms for "contracted" obligations. Researchers working in older pleading documents, corporate charters, or statutory texts should be alert to whether the drafter meant the classical legal sense or was using the word loosely.
Why It Matters in Research
The classical incur/contract distinction shows up most consequentially in three research contexts.
First, in statutory and charter interpretation. When a 19th- or early 20th-century statute, corporate charter, or municipal ordinance limits authority to "debts contracted" or "liabilities incurred," courts treated these as meaningfully different categories. A liability incurred by tort or by operation of law might fall outside a debt limitation but within a liability clause, or vice versa. Overlooking this distinction when reading historical documents will distort the analysis.
Second, in civil procedure and pleading. Older New York practice reports — including the Crandall v. Bryan and Beekman v. Van Dolsen decisions cited in Black's 2nd edition — addressed the incur/contract divide directly in the context of what obligations could be reached by particular forms of action or execution. Researchers in 19th-century New York practice materials will encounter this usage frequently.
Third, in modern contract drafting disputes. Courts interpreting indemnification clauses, fee-shifting provisions, insurance policies, and cost-reimbursement agreements frequently parse whether a cost was "incurred" — meaning actually suffered or imposed — as opposed to merely anticipated or contracted for. The timing of when a liability is "incurred" (versus when it is billed, paid, or claimed) generates recurring litigation. Tax law adds another layer: "incurred" in the context of accrual-method accounting has its own technical meaning tied to the all-events test, which diverges from both the common and the classical legal senses.
Researchers should not assume that "incur" carries the narrow classical meaning in modern documents — but should not assume it has lost that meaning in historical ones.
Historical Dictionary Support
All four source dictionaries converge on the same formulation, some nearly verbatim: men contract debts; they incur liabilities. The liability is "cast upon them by act or operation of law." This alignment is unusually consistent across Bouvier, both Black's editions, and Anderson, suggesting the distinction was well-settled and deliberately emphasized by compilers of the period.
Bouvier and Anderson both reinforce the point that "incur" implies something not embraced by "debt" or "contract" — a residual category for obligations that arise outside voluntary agreement. Anderson's entry briefly cross-references EXPENDITURE, indicating awareness that "incurred" costs in an accounting or fiscal sense were an adjacent usage that merited separate treatment.
What the historical dictionaries do not address is the modern proliferation of "incur" in commercial boilerplate, tax statutes, and insurance policy language — contexts where the word has drifted toward general synonymy with "become subject to" or "suffer." The classical legal meaning is accurate for historical sources but should not be mechanically imported into contemporary documents without checking whether the drafter preserved the distinction.
Jurisdictional Note
The incur/contract distinction appears most explicitly in 19th-century New York case law and was also addressed in Texas authority cited in Black's 2nd edition. The distinction is not uniquely jurisdictional — it reflects general common law usage — but researchers working in early New York practice reports will find it most extensively developed there.