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.
Not sufficient; lacking competent power or ability; unqualified, unequal, unfit.
Not sufficient; of a type or kind that does not suffice, that does not satisfy requirements or needs.
An inadequate quantity of; not enough.
A quantity (of something) that is less than is needed.