- lacking some element or characteristic; defective: deficient in taste.
- insufficient; inadequate: deficient knowledge.
- a person who is deficient, especially one who is mentally defective.
- lacking some essential; incomplete; defective
- inadequate in quantity or supply; insufficient
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).
- Lacking an essential quality or element.
- Inadequate in amount or degree; insufficient.