# deficient

> English word · Adjective · IPA /dɪˈfɪʃənt/ · frequency rank #18,801

## Definitions
1. Lacking something essential; often construed with in.
2. Insufficient or inadequate in amount.
3. Of a number n, Having the sum of divisors σ(n)<2n, or, equivalently, the sum of proper divisors (or aliquot sum) s(n)<n.

## Etymology
From Latin deficiens, present participle of deficere (“to lack, fail, be wanting”); see defect.

## Easily confused with
- **deficit** (https://plainspell.com/en/vs/deficient-vs-deficit)
- **deficiency** (https://plainspell.com/en/vs/deficiency-vs-deficient)

## Common misspellings (13)
`ddeficient`, `defciient`, `defficient`, `deficcient`, `deficeint`, `deficiennt`, `deficientt`, `deficietn`, `deficinet`, `defiicent`, `deifcient`, `dfeicient`, `edficient`

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/deficient