Insufficient or inadequate in amount.
Lacking something essential; often construed with in.
Of a number n, Having the sum of divisors σ(n)<2n, or, equivalently, the sum of proper divisors (or aliquot sum) s(n).
A person who is deficient.
Depleted of resources.
Emptied of contents, especially of air; that has been made into a vacuum.
Very tired; in a state of exhaustion.