In ethics, casuistry is a process of reasoning that seeks to resolve moral problems by extracting or extending abstract rules from a particular case, and reapplying those rules to new instances. This method occurs in applied ethics and jurisprudence. The term is also used pejoratively to criticise the use of clever but unsound reasoning, especially in relation to moral questions. It has been defined as follows:

Study of cases of conscience and a method of solving conflicts of obligations by applying general principles of ethics, religion, and moral theology to particular and concrete cases of human conduct. This frequently demands an extensive knowledge of natural law and equity, civil law, ecclesiastical precepts, and an exceptional skill in interpreting these various norms of conduct....