What does defeasible mean?
"Defeasible" is an adjective meaning capable of being annulled, reversed, or made void. It is chiefly a term of law, where it describes interests, titles, estates, or rights that persist only until some stated condition causes them to end. A person may hold a defeasible fee in land, for example, meaning ownership continues unless a particular event occurs — such as the property ever being used for commercial purposes — at which point the interest terminates. Beyond the courtroom, the word appears in philosophy and everyday reasoning to describe beliefs or conclusions that are provisionally accepted but open to defeat by new evidence. Its opposite, "indefeasible," denotes something that cannot be undone. Because it signals conditional rather than absolute status, "defeasible" is a precise way to convey that an entitlement, however secure it currently seems, rests on terms that could ultimately revoke it.
adjectiveCapable of being annulled, voided, or terminated under certain conditions; not absolute or final. In law, it describes a right, interest, or claim that can be lost if a specified event occurs.
- (Law) Of a right, title, interest, or estate: capable of being rendered void or terminated upon the occurrence of a specified condition or event.
- (General) Capable of being annulled, overturned, or made invalid; not absolute.
"The heir's interest in the estate was defeasible should he fail to meet the conditions set out in the will."
"The tenant held only a defeasible interest in the property, which lapsed when she moved abroad."
"Even widely accepted scientific conclusions remain defeasible in light of new evidence."
A defeasible right looks rock-solid — until the fine print kicks in and takes it away.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of defeasible
"Defeasible" derives from Anglo-Norman and Old French "defaisible", formed on "defaire", meaning "to undo", which traces back through Vulgar Latin to the Latin verb "facere", "to do or make". The same root gives English words such as "fact", "feasible", "feat", and "defeat". The term entered English legal vocabulary in late medieval times, when French was the language of English law, and it remains a fixture of legal terminology today.
Related word forms
How defeasible is actually used
Primarily a formal legal term, most common in property law, contracts, and trusts, though it also appears in philosophy and logic to describe conclusions open to revision when new information emerges. Rare in everyday speech; outside legal writing it can sound technical or pedantic.
Easily confused with defeasible
Indefeasible means the exact opposite — a right that cannot be voided or undone — while defeasible describes rights that can be annulled.