/ˌʌnˌkɒnstɪˌtjuːʃənˈæləti/ – noun
Definition: sự không hợp hiến.
A more thorough explanation: Unconstitutionality refers to the quality or state of being contrary to or in violation of the provisions of a constitution, particularly a written constitution that serves as the supreme law of a country or jurisdiction. When a law, regulation, action, or decision is found to be unconstitutional, it is deemed invalid and unenforceable.
Example: The court ruled that the new law was unconstitutional because it violated the First Amendment rights of the citizens.