Definition of "deontic" [deontic]

• Of, relating to, or concerning duties or obligations: deontic logic. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "I would only add that both will and going to (like most modals or modal phrases) are used to express two kinds of meanings: 1. meanings related to how we see the likelihood of events (sometimes called extrinsic, or epistemic, modality); and meanings related to how we intervene in, or exert change on, events (intrinsic or deontic modality)."
• "A broad division has been made into alethic (regarding theoretical possibility), epistemic (regarding actuality), deontic (regarding duty) and boulomaic (regarding desire)."
• "In fact, just as “must not” can be read as deontic modality rather than epistemic, “should not” can be read as boulomaic modality rather than deontic — the “should not” of desire rather than duty."