Designed or intended to teach; instructive (often pedantically or dictorially so); containing a political or moral message; fond of instructing or advising (even when this is neither welcome nor necessary).
Such teachings, reminding us of the leading thought in the Biblical Book of Ecclesiastes, indicate the didactic character given to ancient tales that were of popular origin, but which were modified and elaborated under the influence of the schools which arose in connection with the Babylonian temples.
Anonymous, An Old Babylonian Version of the Gilgamesh Epic. Amazon
You ought to enjoy the owner's evident enjoyment (he was never bored and therefore never boring), his charmingly ingenuous pride of possession, his shrewd, humorous and excessively didactic utterances about painters, pictures, architecture and female beauty, his zeal for water-colour sketching and his apparently profound contempt of other exponents of the craft.
Unattributed review, Punch, 21 July 1920, of
Arnold Bennett's From the Log of the Velsa. Amazon
Active, participatory styles of delivery are more effective than unstructured or overly didactic methods.
He famously coined a phrase to describe what he abhors in modern fiction: “hysterical realism,” which refers to a style of writing that features rampant caricature, absurd plots and prose, and frequent references to popular culture combined with didactic social commentary.