Sentence:  For, in essence, the <WSD>caveman</WSD> concept implies the abhorrent—undignified human bestiality and a disquieting association with apelike ancestors. <WSD>Cavemen</WSD> have represented Darwin′s repugnant evolutionary ideals and even suggest civilisation′s tenuousness. 
Meaning of the word marked with <WSD> tags:  An early human or closely related species, popularly held to reside in caves.