impracticability

: a doctrine in contract law: relief from obligations under a contract may be granted when performance has been rendered excessively difficult, expensive, or harmful by an unforeseen contingency; also : a defense to breach of contract on the ground that it has been rendered impracticable — called also commercial impracticability, impracticability of performance ; compare frustration, impossibility of performance at impossibility : a defense to breach of contract on the ground that it has been rendered impracticable — called also commercial impracticability, impracticability of performance ; compare frustration, impossibility of performance at impossibility

Note: Under section 2-615 of the Uniform Commercial Code, the impracticability must arise “by the occurrence of a contingency the non-occurrence of which was a basic assumption on which the contract was made” or by compliance with the law.