ethics, especially that branch dealing with duty, moral obligation, and right action.
Origin: 1820–30; < Greekdeont- that which is binding (stem of déon, neuter present participle of deîn to bind), equivalent to de- bind + -ont- present participle suffix + -o- + -logy
1826, from Gk. deont-, comb. form of deon "that which is binding, duty," neut. prp. of dei "is binding;" + -logia "discourse" (see -logy). Related: Deontological (1832).