estoppel

From Old French estoupail or estopail, a bung made of oakum (étoupe), from Latin stuppa ("flax, tow"), from Ancient Greek στύππη (stuppē).

estoppel (countable and uncountable, plural estoppels)

1. (common law) A legal principle in the law of equity that prevents a party from asserting otherwise valid legal rights against another party because of conduct by the first party, or circumstances to which the first party has knowingly contributed, make it unjust for those rights to be asserted.

• collateral estoppel
• estoppel by deed