deontic (adj.) 

A term derived from modal logic and used by some LINGUISTS as part of a theoretical framework for the analysis of MODAL VERBS and related STRUCTURES in LANGUAGE. Deontic modality is concerned with the logic of obligation and permission, e.g. the use of the modals in SENTENCES such as The car must be ready, i.e. ‘It is obligatory that the car be ready’. It thus contrasts with ALETHIC and EPISTEMIC modality, which would interpret this sentence respectively as ‘It is metaphysically necessary for the car to be ready’ and ‘It follows from what is known that the car is ready’.