deficient

adjective

1. lacking some element or characteristic; defective: deficient in taste.
2. insufficient; inadequate: deficient knowledge.

noun

3. a person who is deficient, especially one who is mentally defective.

adjective

1. lacking some essential; incomplete; defective
2. inadequate in quantity or supply; insufficient

adj.

1580s, from Latin deficientem (nominative deficiens), present participle of deficere “to desert, revolt, fail,” from de- “down, away” (see de-) + facere “to do, perform” (see factitious).

adj.

1. Lacking an essential quality or element.
2. Inadequate in amount or degree; insufficient.