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).
A person or group that does not show up.
An absence; failure to show up or to make a scheduled appearance, especially at a hotel or a place of employment.
To fail to show up for something.