English Reference
adjective · noun

inactive

adj. · n.
US /ˌɪˈnæktɪv/ UK /ɪnˈæktɪv/ in·ac·tive

  1. 01 B2 Upper Intermediate

    adj.not doing anything or not working at the moment.

    adj.not currently functioning, operating, or engaged in activity.

    Simple

    The volcano has been inactive for over a hundred years.

    In context

    The account was flagged as inactive after the user failed to log in for six consecutive months.

  2. 02 B2 Upper Intermediate

    adj.not doing much exercise or physical work.

    adj.characterised by a lack of physical exertion or exercise.

    Simple

    If you are inactive for too long, you might start to feel stiff.

    In context

    Medical professionals warn that an inactive lifestyle significantly increases the risk of developing chronic cardiovascular conditions.

  3. 03 C1 Advanced Technical Science

    adj.not causing a chemical reaction.

    adj.exhibiting little or no chemical reactivity under specified conditions.

    Simple

    The gas is inactive and does not react with other chemicals.

    In context

    The catalyst remains inactive until the temperature of the chamber reaches four hundred degrees Celsius.

  4. 04 C2 Proficiency Formal

    n.someone who does not take part in an activity or take action.

    n.a person who remains passive or fails to take necessary action during an event.

    Simple

    The leader criticised the inactives in the group for not helping with the project.

    In context

    The report distinguished between those who protested and the inactives who merely watched from the sidelines.

    idlerlayabout

Understanding inactive black holes is important because most known black holes are dormant, including the one at the center of the Milky Way.

ScienceDaily· 6 Aug 2026

When the light is turned off and the material cools, the lysozyme reverts to its inactive form.

Smithsonian Magazine· 17 Jun 2026

From French inactif. See also earlier unactive.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Origin French inactif
Level B2 · Upper Intermediate
Frequency Frequent
Updated