“合同落空”“合同受挫”在英语合同中对应的专业术语是frustration， 另外常见的英语的表达是frustration of contract或frustration of purpose。 

例：The Parties to a contract may be disharged from the necessity of further performance if the contract becomes frustrated. A contract maybe come frustrated where, before property and risk have passed, it becomes impossible to perform the contract legally, (or the circumstance so change that performance would be radically different from what was; contemplated in thecontract. The frustrating event must occur without the fault of either party.Examples of frustrating events are the outbreak of war or a supervening illegality, i.e. where performance becomes illegal by law after the contract is made. (合同落空，当事人可不再继续履行合同。合同无法依法履行或因情势变更，合同的履行与合同规定大相径庭，在财产与风险转移之前，合同可以落空。发生合同落空事项，当事人均不得有过错。合同落空的情况如战争爆发或合同订立后随即发生非法行为，即合同于订立后其履行即为非法。)

以上参考《法律英语核心词汇：实务基础》（屈文生）