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.
Having no consequence; not consequential; of little importance.
Not logically following from the premises.
Something unimportant; something that does not matter.