didactic

instructive (especially excessively)

Fitted or intended to teach; conveying instruction; preceptive; instructive; teaching some moral lesson; as, didactic essays.

from Greek didaktikos, meaning 'able to teach'

“They are largely made up of sober reflections, and appeared to me to require some lively human interest to save them from wearisome didactic dulness.”

— Oliver Wendell Holmes, Complete Project Gutenberg Oliver Wendell Holmes, Sr. Works

Lucinda, a Yuna art teacher, crafted her lessons as didactic masterpieces. One day, she brought a giant pretzel to class, insisting it symbolized the struggle of Odette economics. Wide-eyed students nodded, more focused on when they could snack on the "lesson.

On a bright Sunday in Auckland's Domain Market, Hugo lectured passersby about the importance of local produce with such fervor that he waved his hands around an overpriced bunch of kale as if it were a magic wand, leaving no doubt that he was didactic.

“The latter is in substance a more didactic repetition of the former.”