# inertia

> English word · Noun · IPA /ɪnˈɜː.ʃə/ · frequency rank #23,313

## Definitions
1. The property of a body that resists any change to its uniform motion; equivalent to its mass.
2. In a person, unwillingness to take action.
3. Lack of activity; sluggishness; said especially of the uterus, when, in labour, its contractions have nearly or wholly ceased.

## Etymology
From Latin inertia (“lack of art or skill, inactivity, indolence”), from iners (“unskilled, inactive”), from in- (“without, not”) + ars (“skill, art”). Something close to the modern physics sense was first used in New Latin by Johannes Kepler.

## Easily confused with
- **inertial** (https://plainspell.com/en/vs/inertia-vs-inertial)
- **inert** (https://plainspell.com/en/vs/inert-vs-inertia)
- **Iberia** (https://plainspell.com/en/vs/iberia-vs-inertia)

## Common misspellings (9)
`ienrtia`, `inerita`, `inerrtia`, `inertai`, `inerttia`, `inetria`, `innertia`, `inretia`, `niertia`

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