Definitionen
1.AdjectiveLacking something essential; often construed with in."They were deficient in social skills."
2.AdjectiveInsufficient or inadequate in amount.
3.AdjectiveOf a number n, Having the sum of divisors σ(n)<2n, or, equivalently, the sum of proper divisors (or aliquot sum) s(n)<n.
4.NounA person who is deficient.