noun
primitive man; prehistoric human
Refers to early humans or hominids from prehistoric times, often in anthropological or historical contexts. Can also be used figuratively to describe someone with crude or unsophisticated behavior.
博物館で原始人の化石を見た。
I saw a fossil of a primitive human at the museum.
彼の乱暴な態度はまるで原始人のようだ。
His rough behavior is just like that of a primitive man.
古代人 means 'ancient people' and typically refers to humans from early historical civilizations, whereas 原始人 points to pre-civilization, Stone Age humans.
Compound of 原始 (primitive, original) and 人 (person). The term is a modern coinage used in anthropology and history to describe early humans.