i-adjective
Describes a surface or object that is physically flat, without bumps or curves. Similar to 平たい (ひらたい), but with an emphatic or colloquial feel from the geminated った.
See also: 平たい
この道は平ったくて歩きやすい。
This road is flat and easy to walk on.
平ったい石を拾って水切りをした。
I picked up a flat stone and skipped it on the water.
i-adjective
plain; simple (language, words)
Used for speech or writing that is straightforward, easy to understand, and without embellishment. Often implies a lack of complexity or formality.
See also: 平たい
難しい言葉を使わずに、平ったい表現で説明してください。
Please explain it in plain language, without using difficult words.
彼の文章は平ったくて、誰にでもわかる。
His writing is simple and anyone can understand it.