dumb down

English

dumb down (third-person singular simple present dumbs down, present participle dumbing down, simple past and past participle dumbed down)

(idiomatic, transitive) To convey some subject matter in simple terms, avoiding technical or academic language, especially in a way that is considered condescending.
The public won't understand this concept. We need to dumb down our explanation of it.
(idiomatic, intransitive) To become simpler in expression or content; to become unacceptably simplistic.
Television has really dumbed down over the past ten years.

to convey some subject matter in simple terms

to become unacceptably simplicistic