1. the use of clever but misleading reasoning to justify something that is morally wrong or questionable
Usage: typically used in a critical or disapproving sense
2. the application of general moral principles to specific cases, especially in theology or ethics
Usage: formal or academic usage; less common in everyday speech

Examples

• The politician's casuistry allowed him to claim he had kept his promise while actually breaking it.
• Her argument was pure casuistry—technically correct but designed to mislead.
• The lawyer's casuistry twisted the facts to support an indefensible position.
• He used casuistry to justify behavior that most people would consider unethical.
• The company's casuistry about environmental impact fooled no one.
• Medieval theologians engaged in casuistry to resolve complex moral dilemmas.
• His casuistry was so transparent that even his supporters rolled their eyes.