# inert

/ˌɪˈnɝt/ (US) · /ɪnˈɜːt/ (UK) · CEFR C1 · Adjective

Source: https://englishreference.com/word/inert
Updated: 2026-05-08

## Definition

not moving or not having the power to move. In science, it describes a gas or substance that does not react with other chemicals.

For teachers: lacking the ability or strength to move; chemically inactive. Often describes substances that do not undergo chemical reactions under a set of given conditions.

## Examples

- Helium is an inert gas.
- The patient lay inert on the bed while the doctors performed their final checks before the procedure.
- While the noble gases are famously inert, modern chemistry has demonstrated that even they can be forced into compounds under extreme laboratory conditions of pressure and temperature.

## Usage notes

- Often used predicatively after linking verbs like 'remain' or 'lie'.

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