Deontology determines a moral framework for right and wrong — basically, rules for how to live your life. The names of philosophies usually have a root that can be converted into other parts of speech. “Deont-” is Greek for “being needed or necessary,” and the noun “deontology” is the name for an ethical rule-following philosophy. Another noun, “deontologist,” refers to one who practices or studies that philosophy. And “deontological,” an adjective, describes anything that follows the principles of deontology.