The word 缺陷 is formed by combining two characters, each contributing a vivid conceptual image to convey the idea of a flaw or defect. 缺 means "to lack" or "be deficient", suggesting an absence or shortfall. 陷 means "to sink" or "a pitfall", evoking the image of a hollow, trap, or sunken imperfection in a surface. Together, they metaphorically create the notion of a "deficient pit" or a "lacking sinkhole", an inherent weakness or faulty area that is both missing something essential and structurally unsound.