/ˈkʌstəˌmɛri ˌɪntərˈnæʃənəl lɔː/ – Phrase
Definition: luật tập quán quốc tế.
A more thorough explanation: Customary international law refers to a body of unwritten rules and practices that have developed over time through consistent state practice and are considered legally binding on all states. It is a source of international law that is derived from the general and consistent practice of states followed out of a sense of legal obligation.
Example: Under customary international law, states are expected to respect the principle of non-intervention in the internal affairs of other states.