Deficient In: Standard Pattern
Deficient In: Standard Pattern records a directly documented English construction and keeps guidance bounded to the evidenced pattern rather than inventing a broader prohibition.
Use “deficient in” for something that lacks enough of a substance, quality, skill, or other needed element.
Key details
Choose the right form
| Meaning / situation | Form / construction | Decision |
|---|---|---|
| something lacks enough of a substance, quality, skill, or needed element | deficient in + noun | Use the documented “in” complement. |
| the missing element is not named | deficient | The adjective can stand without the complement. |
| a different relationship is intended | choose a construction that matches it | Do not treat “in” as a universal complement for every sense or structure. |
Quick tests
Meaning / construction test
Are you naming the substance, quality, skill, or element that is lacking?
If yes: Use “deficient in.”
If no: Use the adjective alone or another construction if the missing element is not being named.
Caveat: Choose by the documented meaning or construction; a different pattern may be valid in a different sentence structure or variety.
Examples
The report was deficient in supporting detail.
The “in” phrase names what is lacking.
The diet may be deficient in iron.
The complement identifies the lacking substance.
The first draft was clearly deficient.
No complement is needed when the deficiency is understood from context.
Further guidance
Construction
Use “deficient in” for something that lacks enough of a substance, quality, skill, or other needed element.
Style Boundary
The page records the documented “in” complement and does not turn every use of “deficient” into a mandatory prepositional phrase.
Sources and evidence
Sources are shown with the role they play in this guide. Historical or style-sensitive claims are kept within the evidence boundary described above.
- DEFICIENT | English meaning — Cambridge Dictionary (opens in a new tab)Cambridge Dictionary · Direct dictionary evidence for the adjective construction “deficient in”.