A person who is deficient.
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).
One who is disabled. (often used collectively as the disabled, but sometimes also singular)
Made incapable of use or action.
Having a disability.
Legally disqualified.