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 who is indifferent or apathetic.
Indicating or reflecting a lack of concern or care.
Ambivalent; unconcerned; uninterested, apathetic.
Having no preference.
Mediocre (usually used negatively in modern usage).
Not making a difference; without significance or importance.
Being in the state of neutral equilibrium.