- demoralize c.1793, "to corrupt the morals of," from Fr. démoraliser, from de- "remove" (see DE- (Cf. de-)) + moral (adj.) (see MORAL (Cf. moral)). Said to be a coinage of the French Revolution. Sense of "lower the morale of" (especially of armies) is first recorded 1848. Related: Demoralized; demoralizing.
Etymology dictionary. 2014.