Metaethics is a branch of philosophy that deals with the nature, scope, and meaning of moral judgment. It is one of the three branches of ethics studied by philosophers, the others being normative ethics and applied ethics. Metaethics is concerned with the foundations of morality and moral reasoning, and it attempts to understand the assumptions underlying normative theories. Some of the key issues that fall within the purview of metaethics include:

• Nature of morality: Metaethics asks questions such as "What is morality?" and "Whats its nature like?". It seeks to understand whether morality is an objective thing out there in the world waiting to be known or whether it is more like a preference, an opinion, or just a bunch of cultural conventions.

• Moral language: Metaethics is concerned with the language used to express moral judgments and the meaning of moral terms. It explores the presuppositions and commitments of moral thought, talk, and practice and abstracts away from particular moral judgments.

• Foundations of morality: Metaethics explores where moral values originate, what it means to say something is right or good, whether there are any objective moral facts, whether morality is (culturally) relative, and whether there is a psychological basis for moral practices and value judgments.

• Ontology of value: Metaethics is also concerned with the ontology of value, which is the study of the being of value. It seeks to understand the nature of what makes something valuable and what it means to say that something is good or bad.

Overall, metaethics is a highly abstract and theoretical field that seeks to understand the foundations of morality and moral reasoning. It is often contrasted with normative ethics, which is concerned with evaluating specific practices and principles of action, and applied ethics, which is concerned with the practical application of ethical principles to real-world situations.