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).
The result of being impaired
A deterioration or weakening
A downward revaluation, a write-down.
A disability or handicap
an inefficient part or factor.