/oʊˈpiniːoʊ ˈdʒʊrɪs/ – Latin phrase
Definition: sự tin chắc vào tính hợp pháp.
A more thorough explanation: Opinio juris is a Latin term used in international law to refer to the belief or opinion that a certain practice is required by law. It is an important element in establishing a customary international law norm, as it reflects the belief that a particular action is legally required rather than merely a matter of courtesy or convenience.
Example: In the case of Smith v. Jones, the court considered whether the defendant’s actions were in line with opinio juris, or the established legal opinion within the jurisdiction.