Didactic refers to something that is intended to teach something or demonstrate something, especially something to do with morality. Didactic instruction is characterized as ponderous, boring, or pushing a moral agenda in an underhanded fashion. Didactic comes from the Greek word didaktikosm, which means apt at teaching. Didactic is an adjective, related words are didactically, didacticism.
Pedantic means focusing too much on trivial details when discussing or teaching material. A pedantic person is not discerning when considering which items or facts are important and which items or facts are unimportant. A pedantic person’s scholarship is often questionable. Pedantic is an adjective, it comes from the French word pédantesque. Related words are pedant, pedantically.
Examples
States one of the show’s didactic panels: “Marking the skin places people in relationships that are social, political and cosmological.” (The Globe and Mail)
“Science Fair: An Opera With Experiments” is an entertaining, sometimes poetic and unapologetically didactic concoction made up of song, science lectures and demonstrations. (The New York Times)
Often the didactic panels that accompany the art in a museum or gallery offer a quick explanation of the work at hand. (The Montreal Gazette)
They also need to change their instructional practices, which are almost exclusively didactic (teacher talks, kids listen), to include more student engagement and cooperative and problem-based learning. (The Mercury News)
Though I sort of treasured the faux-fascinated looks on the faces of the actors who had to act like this was a revelation, rather than the most joylessly pedantic version of rock and roll history this side of the Grammys. (GQ Magazine)
William, who is married to timid Mary, is a pedantic bully, expertly played by Ayckbourn specialist Matthew Cottle. (The Evening Standard)
It may seem pedantic to be bringing these apparently minor matters to light at this stage, but not implementing the rules in these cases gives the offending team a major advantage in games that are increasingly being decided on the smallest of margins. (The Irish Examiner)