- a rendering null and void.
- a condition on the performance of which a deed or other instrument is defeated or rendered void.
- a collateral deed or other writing embodying such a condition.
noun mainly law
- the act or process of rendering null and void; annulment
- a condition, the fulfilment of which renders a deed void
- the document containing such a condition
early 15c., from Anglo-French defesaunce, Old French desfaisance “undoing, destruction,” from desfaire (Modern French défaire) “to undo, destroy” (see defeat (v.)). Related: Defease; defeasible.