deon-, deont- +

(Greek: duty, that which is binding; obligation; necessity)

deontic
Relating to the concept of moral obligation.
deontic logic
The field of logic that is concerned with obligation, permission, and related concepts.
deontological
Relating to philosophical theories that state that the moral content of an action is not wholly dependent on its consequences.
deontological ethics
The branch of ethics dealing with right action and the nature of duty, without regard to the goodness or value of motives or the desirability of the ends of any act.
deontologism
Emphasis on universal imperatives; such moral laws, duties, obligations, prohibitions, and the like (sometimes also called imperativism).

Deontologism is usually contrasted with teleologism (an emphasis on goals) or consequentialism (an emphasis on results); but sometimes it is also contrasted with egoism or eudaimonism (an emphasis on personal happiness or fulfillment as opposed to conformance with moral imperatives).

deontologist
Someone who practices deontology; that is, duty or moral obligation.
deontology
The science of duty; that branch of knowledge which deals with moral obligations.

Coined by the English philosopher Jeremy Bentham (1748-1832) in 1826.