Of a number n, Having the sum of divisors σ(n)<2n, or, equivalently, the sum of proper divisors (or aliquot sum) s(n).
Insufficient or inadequate in amount.
Lacking something essential; often construed with in.
A person who is deficient.
Complete; full; entire; absolute.
Fully attended; for everyone's attendance.
Part of a lesson, usually at or towards the end, designed to review or evaluate the learning that has taken place.
plenary session