1ADJ [usually verb-link ADJ]缺乏的;缺少的;不足的 If someone or something is deficient in a particular thing, they do not have the full amount of it that they need in order to function normally or work properly. 缺乏的;缺少的;不足的 [formal]
...a diet deficient in vitamin B. [+ in]
缺乏维生素 B 的饮食
Deficient is also a combining form.
Vegetarians can become iron-deficient.
素食者可能会缺铁。
2ADJ-GRADED 有缺点的;有缺陷的;不完善的 Someone or something that is deficient is not good enough for a particular purpose. 有缺点的;有缺陷的;不完善的 [formal]