What term describes a non-codified form of law based on long-accepted customs and traditions?

The term that describes a non-codified form of law based on long-accepted customs and traditions is common law. Common law develops through judicial decisions and precedents rather than through written statutes or regulations. It relies heavily on interpretative rulings of judges in past cases, which serve as a guide for future cases involving similar issues. This law evolves over time as society's values and norms change, allowing it to remain relevant.

In contrast, statutory law is created by legislative bodies and consists of laws that are formally written and codified. Civil law refers to a legal system codified in comprehensive statutes, typically found in countries with a civil law system. Administrative law governs the activities of administrative agencies and includes regulations made by government bodies. Thus, common law stands out as it arises organically from societal practices rather than from explicit legislative enactments.