na-adjective, noun
Describes language, explanations, or content that is easy to understand and not overly complex. Often used for writing style or speech.
この本は平易な言葉で書かれている。
This book is written in simple language.
先生は難しい概念を平易に説明した。
The teacher explained the difficult concept in an easy-to-understand way.
簡単 is a more general word for 'easy' or 'simple', used for tasks, problems, or things. 平易 specifically refers to ease of understanding, especially in language or explanations.
易しい is a common i-adjective for 'easy' in a broad sense. 平易 is more formal and often used in written or academic contexts to describe clarity.
Composed of 平 (flat, even, calm) and 易 (easy, simple). The combination suggests something leveled and straightforward, hence easy to grasp.