√ Frasa tidak sah di sini saya tafsirkan tidak berkekuatan dan berpengaruh hukum. Gampangnya, tidak bermakna apa-apa secara hukum.

√ Kata yang bisa mewakili adalah invalid. Dari kamus hukum Merriam-Webster: invalid being without force or effect under the law.

★ Surjaya berikut menceritakan kekuasaan MA Uni Eropa untuk menidaksahkan peraturan perundangan di bawah konstitusi, sekalipun sempat diberlakukan.

SURJAYA ★★★★★
https://books.google.com/books?id=9jGA5sfKTeYC&pg=SL252-PA13...
The Supreme Court may, after the constitutional review proceedings, declare invalid legislation or a provision thereof which has entered into force...

http://lasteombudsman.ee/en/the-chancellor-of-justice-turned...
The Chancellor of Justice submitted an application to the Supreme Court to declare invalid the provision of the Code of Criminal Procedure ...

https://books.google.com/books?id=qWlMgSqhRv4C&pg=PA249&lpg=...
...the power of the Supreme Court to declare invalid acts of Congress that violate the Constitution.