If a film, a book, or a person is preachy, they try too hard to push a lesson or an opinion — and the speaker does not like it. The word always complains a little. A preachy story keeps stopping to tell you how you should think. A preachy friend sounds as if they are giving a sermon at the dinner table. It comes from preach, the church-speaking word, though actually you use preachy about school talks, adverts, and parents too: anywhere the moral is too loud. It does not mean the idea is wrong. It means the way of saying it feels heavy, as if they know better than you.

說教的、愛講大道理的（帶嫌棄；不是中性的「有教育意義」）