/ʌnˈrɪtən ˌkɑnstɪˈtuʃən/ – Phrase
Definition: hiến pháp bất thành văn.
A more thorough explanation: An unwritten constitution refers to a system of government where the fundamental principles and rules governing the state are not codified in a single document or set of documents, but are instead derived from a combination of statutes, conventions, judicial decisions, and historical documents. This type of constitution relies on traditions, customs, and practices to guide the functioning of the government and the relationship between the state and its citizens.
Example: In the United Kingdom, the unwritten constitution is based on conventions, statutes, and judicial decisions rather than a single written document.