What is the meaning of Deficient?

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)<n.

A person who is deficient.

deficient

third-person plural future active indicative of dēficiō

deficient

Source: wiktionary.org