Lacking something essential; often construed with in.
Insufficient or inadequate in amount.
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.
Unruly, troublesome; not easily guided.
Unfavourable, adverse, or disadvantageous.
Unseemly, improper.