Unenforceable contract，翻译为“不可强制执行的合同”或“无强制执行效力合同”，指当事人向法院诉请强制执行时，法院不予承认、不子强制执行的合同。

Unenforceable contract属于有效合同，但因存在某些技术缺陷而不能得到强制执行。该种合同虽有某些法律后果，但当其面临某些抗辩——诸如防止欺诈法——时，则当事人不能提出损害赔偿或实际履行之诉，从而要求强制执行合同。

根据《防止欺诈法》〔Statute of Frauds〕，合同须具备书面证据，则缺乏书面证据的该种合同即属不可强制执行的合同。

Voidable contract，翻译为“可撤销合同”

Voidable contract是指合同因欠缺一定的生效要件，其有效与否，取决于有撤销权的一方当事人是否行使撤销权的合同。

可撤销合同是一种相对有效的合同，在有撤销权的一方行使撤销权之前，合同对双方当事人都是有效的。它是一种相对无效的合同，但又不同于绝对无效的无效合同。

因虚假陈述订立的合同就是可撤销合同。

参考双语法规：

《民法典》第一百四十七条：

基于重大误解实施的民事法律行为，行为人有权请求人民法院或者仲裁机构予以撤销。

Where a civil juristic act is performed based on serious misunderstanding, the person who performs the act has the right to request the people’s court or an arbitration institution to revoke the act

《民法典》第一百四十八条：

一方以欺诈手段，使对方在违背真实意思的情况下实施的民事法律行为，受欺诈方有权请求人民法院或者仲裁机构予以撤销。

Where a party by fraudulent means induces the other party to perform a civil juristic act against the latter’s true intention, the defrauded party has the right to request the people’s court or an arbitration institution to revoke the act.

《民法典》第一百四十九条：

第三人实施欺诈行为，使一方在违背真实意思的情况下实施的民事法律行为，对方知道或者应当知道该欺诈行为的，受欺诈方有权请求人民法院或者仲裁机构予以撤销。

Where a party knows or should have known that a civil juristic act performed by the other party is based on a third person’s fraudulent act and is against the other party’s true intention, the defrauded party has the right to request the people’s court or an arbitration institution to revoke the civil juristic act.

《民法典》第一百五十条：

一方或者第三人以胁迫手段，使对方在违背真实意思的情况下实施的民事法律行为，受胁迫方有权请求人民法院或者仲裁机构予以撤销。

Where a party performs a civil juristic act against its true intention owing to duress of the other party or a third person, the coerced party has the right to request the people’s court or an arbitration institution to revoke the civil juristic act.

《民法典》第一百五十一条：

一方利用对方处于危困状态、缺乏判断能力等情形，致使民事法律行为成立时显失公平的，受损害方有权请求人民法院或者仲裁机构予以撤销。

In situations such as where one party takes advantage of the other party that is in a desperate situation or lacks the ability of making judgment, and as a result the civil juristic act thus performed is obviously unfair, the damaged party is entitled to request the people’s court or an arbitration institution to revoke the act.

参考双语例句：

If any of these Terms and Conditions should be determined to be illegal, invalid or otherwise unenforceable by reason of the laws of any state or country in which these Terms and Conditions are intended to be effective, then to the extent and within the jurisdiction in which that Term or Condition is illegal, invalid or unenforceable, it shall be deemed modified as may be necessary to make it valid and enforceable, and if this is not possible, it shall be severed and deleted from the Terms and Conditions and the remaining Terms and Conditions shall survive, remain in full force and effect and continue to be binding and enforceable.

若任何这些条款和条件，由于任何国家或州的法律的原因，被认定为非法、无效，或不可强制执行，虽然这些条款及细则的目的是有效的，但在该管辖范围内，这些条款或细则是非法、无效或不可执行的，则应被视为修改是必要的，以使其有效和可执行，若不能被修改，则应从这些条款及细则中去掉、删除，其余条款和细则仍然适用、有效，并继续具有约束力和强制执行力。

If at any time one or more provisions hereof is or becomes invalid, illegal, unenforceable or incapable of performance in any respect under the laws of any Relevant Jurisdiction, the validity, legality, enforceability or performance in that jurisdiction of the remaining provisions hereof or the validity, legality, enforceability or performance under the laws of any other Relevant Jurisdiction of these or any other provisions hereof shall not thereby in any way be affected or impaired.

倘于任何时间，根据任何相关司法权区法律，本文一条或多条条款在任何方面属或成为无效、非法、不可强制执行或无法履行，其馀条款于该司法权区的有效性、合法性、可强制执行性或可履行性或本文中该等或任何其他条款于任何其他相关司法权区的有效性、合法性、可强制执行性或可履行性概不会因此受到任何影响或损害。

But this dilemma exists in all cases of contracts with infants and scarcely justifies special treatment of the four voidable contracts.

但这种情况在所有与孩童订立的契约均属存在，实不足以支持四种可予撒销契约应予特别处理的做法。

It might therefore be argued that a guarantee of a minor's obligations under a voidable contract should be enforceable prior to its repudiation, although it is only likely to be in such circumstances that the guarantee would be important.

不过，该案是根据一八七四年孩童保障法判决的，保障法判令案中的契约无效，因此可引起争论，虽然一份可予撒销契约在其捨弃前对担保方具有意义，但为一名未成年人在该份契约的义务所作出的担保，在契约舍弃前仍为可履行者。