inert

adjective

in·​ert i-ˈnərt 

1

: lacking the power to move

an inert and lifeless body

2

: very slow to move or act : sluggish

an inert administration

3

: deficient in active properties

especially : lacking a usual or anticipated chemical or biological action

inert noun

inertly adverb

inertness noun

Synonyms of inert

• dormant
• off
• vacant
• idle
• unused

Choose the Right Synonym for inert

inactive, idle, inert, passive, supine mean not engaged in work or activity.

inactive applies to anyone or anything not in action or in operation or at work.

on inactive status as an astronaut

inactive accounts

idle applies to persons that are not busy or occupied or to their powers or their implements.

workers were idle in the fields

inert as applied to things implies powerlessness to move or to affect other things; as applied to persons it suggests an inherent or habitual indisposition to activity.

inert ingredients in drugs

an inert citizenry

passive implies immobility or lack of normally expected response to an external force or influence and often suggests deliberate submissiveness or self-control.

passive resistance

supine applies only to persons and commonly implies abjectness or indolence.

a supine willingness to play the fool

Examples of inert in a Sentence

an inert and lifeless body

How does he propose to stimulate the inert economy and create jobs?

Recent Examples on the Web

Choose ones made from BPA-free, odorless, and chemically inert polypropylene. — Mary Marlowe Leverette, Southern Living, 18 July 2026

Her son has a memory of her flat on her back on her bed, in a white nightgown, a type of inert mother he can sometimes be calmed by. — Diane Williams, New Yorker, 16 July 2026

The rest, in this case about 79% of the bag, is inert ingredients and, sometimes, trace amounts of other nutrients such as calcium, boron, or iron. — Andy Wilcox, Better Homes & Gardens, 16 July 2026

An inert helium atmosphere is not the same as our dynamic, chemically interactive air blanket made principally of nitrogen and oxygen, as well as methane, carbon dioxide, water vapor, and more. — Jeffrey Kluger, Time, 16 July 2026

Word History

Etymology

Latin inert-, iners unskilled, idle, from in- + art-, ars skill — more at arm

First Known Use

1647, in the meaning defined at sense 1

Phrases Containing inert

• inert gas

Rhymes for inert

• alert
• assert
• avert
• dessert
• divert
• evert
• exert
• insert
• invert
• nightshirt
• overt
• revert

Kids Definition

inert

adjective

in·​ert in-ˈərt 

: unable or slow to move, act, or react

inert ingredients in cough medicine

inert gas

inertly adverb

inertness noun

Medical Definition

inert

adjective

in·​ert in-ˈərt 

1

: lacking the power to move

2

: deficient in active properties

especially : lacking a usual or anticipated chemical or biological action

an inert drug

inertness noun