deficient

Meanings

1. 1adjectivenot comparable

   Not having enough of something that is needed or expected.

   Grammar: Used after linking verbs like be, seem, or become; often followed by in: deficient in vitamin C.

   Patterns

   • deficient in something
   • nutritionally deficient
   • seriously deficient

   The doctor said my diet was deficient in iron and recommended supplements.

   The soil here is deficient in nitrogen, so crops grow poorly.

   His essay was well written but deficient in original ideas.

2. 2adjectivenot comparable

   Not reaching a required standard; inadequate or faulty.

   Grammar: Often used before a noun: a deficient system, or after a linking verb: the system is deficient.

   Patterns

   • a deficient system
   • seriously deficient
   • found deficient

   The school was criticized for its deficient safety procedures.

   The building failed inspection because of deficient wiring.

   If the product is deficient, you can ask for a refund.

Common combinations

deficient in

Many people are deficient in vitamin D during the winter.

nutritionally deficient

The children were nutritionally deficient and needed better meals.

deficient diet

A deficient diet can lead to serious health problems.

mentally deficient

The term 'mentally deficient' is now considered outdated and offensive.

Synonyms and how they differ

lacking

More common in everyday speech and usually followed by in: lacking in confidence.

inadequate

Focuses on not being good enough rather than on a missing amount or element.

insufficient

Used mainly about amounts that are too small, not about general quality.

Opposites

Word family

deficiency noun

A lack or shortage of something necessary, such as a vitamin deficiency.

deficit noun

The amount by which something is too small, especially money.

Commonly confused: deficient or defective?

Practice

Make it your own

Write a sentence using “deficient”, then check it and compare it with the examples above.

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