1Describing something primitive, rudimentary, or undeveloped; can also mean original or instinctive (basic, primal).
原始的な道具しかなかった時代の生活を学ぶ。
We study the lives from periods that had only primitive tools.
彼の怒りは理性を欠いた原始的な反応だった。
His anger was a primitive reaction lacking reason.
その社会制度はまだ原始的で多くの改善が必要だ。
That social system is still primitive and needs many improvements.