What does "deficient" mean?

Deficient: Wanting, to make up completeness; wanting, as regards a requirement; not sufficient; inadequate; defective; imperfect; incomplete; lacking; as, deficient parts; deficient estate; deficient strength; deficient in judgment. The style was indeed deficient in ease and variety. Macaulay. Deficient number. (Arith.) See under Abundant. -- De*fi"cient-ly, adv.