Deontic

Part of speech: adjective

Pronunciation: /diːˈɒntɪk/

Definitions

1. Concerning principles of duty, moral obligation, or what one ought to do
2. Pertaining to requirements or rules governing ethical behavior and responsibilities
3. Involving concepts of duty, obligation, and normative guidelines in actions

Etymology: Ancient Greek "déon" meant "what is needful" or "what is right," and it is the neuter participle of "dei," "it is necessary." That single root carries the whole idea of obligation: something that must be done, rather than something that is merely desirable. English "deontic" adds the adjective-forming "-ic" to this Greek stem, so it describes whatever belongs to the realm of duty. The word sits in the same family as "deontology," the ethical theory that judges actions by whether they fulfil duties, not by their outcomes. Philosophers use "deontic" more narrowly as well, in logic, for statements about what is obligatory, permitted, or forbidden. The Greek sense of necessity has thus narrowed from a general "it must be" into a technical vocabulary of moral and logical obligation.