noun
cave dweller; caveman
Refers to a person who lives in a cave, either in prehistoric times or in a modern primitive context. The word is neutral and descriptive.
穴居人は洞窟で生活していた。
Cave dwellers lived in caves.
この遺跡から穴居人の道具が発見された。
Tools of cave dwellers were discovered at this site.
洞窟人 is a synonym also meaning 'cave man', but 穴居人 is more literary and less common.
Compound of 穴居 (けっきょ, 'living in a cave') and 人 (じん, 'person'). The exact historical derivation is uncertain, but the kanji directly convey the meaning.