1.
If someone or something is ~ in a particular thing, they do not have the full amount of it that they need in order to function normally or work properly. (FORMAL)
...a diet ~ in vitamin B.
= lacking
ADJ: usu v-link ADJ, usu ADJ in n
•
Deficient is also a combining form.
Vegetarians can become iron-~.
COMB in ADJ
2.
Someone or something that is ~ is not good enough for a particular purpose. (FORMAL)
...~ landing systems.
= inadequate
ADJ