What does it mean to say that a philosophical theory is deontological?

Deontoligoal ethics, also known as duty-based ethics, are concerned with what people do, not with the consequences of their actions. Deontology teaches that some actions are right or wrong in themselves, regardless of the consequences. Deontologists live by a set of moral rules, such as 'it is wrong to kill' or 'it is right to keep promises'. They decide which actions are right and wrong and believe that a person is good if they are doing a morally right action. Some of the arguments for deontological ethics include that they emphasize the value of every human being, that they make clear what actions must never be done and that they provide certainty. An example of deontological ethics is Kant's Categorical Imperative, which states that moral rules must be universalisable.