What it means
A contract is frustrated when, after it is formed, an unforeseen event makes performance impossible, illegal, or radically different from what the parties agreed — and neither party is at fault. Examples include the destruction of essential subject matter or a change in the law. Frustration automatically discharges the contract from the moment of the frustrating event, releasing both parties from future obligations. The bar is high: a contract is not frustrated merely because it has become harder, more expensive, or less profitable to perform.
How it's used
When the historic hall booked for the wedding burned down before the date, the venue contract was frustrated and both parties were released.