Defective vs. Deficient — What's the Difference?

Having or showing a defect; faulty

Lacking an essential quality or element

(Grammar) Lacking one or more of the inflected forms normal for a particular category of word, as the verb may in English.

Inadequate in amount or degree; insufficient

One who has a physical or mental disability.

Lacking something essential; often construed with in.

Having one or more defects.

Insufficient or inadequate in amount.

Lacking some forms; e.g., having only one tense or being usable only in the third person.

Of a number n, Having the sum of divisors σ(n)<2n, or, equivalently, the sum of proper divisors (or aliquot sum) s(n).

Having a root whose final consonant is weak (ي, و, or ء).

A person who is deficient.

Not capable of representing all the phonemic distinctions of a language it is used to write.

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.

(chiefly of abjad script) Spelled without matres lectionis, for example t=courage as opposed to the plene spelling אומץ where the letter vav ⟨ו⟩ indicates the vowel o.

Inadequate in amount or degree;

(chiefly of abjad script) Without matres lectionis (letters indicating vowels) written out.

Of a quantity not able to fulfill a need or requirement;

A person or thing considered to be defective.

Falling short of some prescribed norm;

(chiefly of abjad script) A word written without matres lectionis (letters indicating vowels).

Wanting in something; incomplete; lacking a part; deficient; imperfect; faulty; - applied either to natural or moral qualities; as, a defective limb; defective timber; a defective copy or account; a defective character; defective rules.

Lacking some of the usual forms of declension or conjugation; as, a defective noun or verb.

Anything that is defective or lacking in some respect.

One who is lacking physically or mentally.

Having a defect;

Markedly subnormal in structure or function or intelligence or behavior;

Not working properly;