flat; level; even — having a smooth, even surface without bumps or irregularities.
この道は平坦なので自転車で走りやすい。
This road is flat, so it's easy to ride a bicycle on.
庭の地面を平坦に均してから芝を植えた。
We leveled the yard's ground and then planted the lawn.
絵画の表面はよく手入れされており、とても平坦だ。
The painting's surface is well maintained and very even.
calm; uneventful; uncomplicated — lacking ups and downs or complications; steady and uneventful.
彼の人生は平坦ではなく、幾度も困難を乗り越えてきた。
His life has not been smooth; he has overcome many hardships.
プロジェクトは順調に進み、問題はなく平坦に終わった。
The project proceeded smoothly and finished without problems.
平坦な議論ではなく、もっと深い検討が必要だ。
We need deeper examination, not a superficial (uneventful) discussion.