deficient
adjective uk/dɪˈfɪʃ.ənt/ us/dɪˈfɪʃ.ənt/
缺乏的，缺少的
not having enough of
A diet deficient in vitamin D may cause the disease rickets. 饮食中缺乏维生素D可导致佝偻病。
不够的，不足的
not good enough
His theory is deficient in several respects. 他的理论有几个方面的不足。