inertia

noun in·er·tia \ i-ˈnər-shə , -shē-ə \

|Updated on: 19 Aug 2018

Definition of inertia

1 a : a property of matter by which it remains at rest or in uniform motion in the same straight line unless acted upon by some external force

b : an analogous property of other physical quantities (such as electricity)

2 : indisposition to motion, exertion, or change : inertness

—

inertial

play \i-ˈnər-shəl, -shē-əl\ adjective

—

inertially

play \i-ˈnər-sh(ə-)lē\ adverb

See inertia defined for English-language learners

See inertia defined for kids

Examples of inertia in a Sentence

He blames governmental inertia for the holdup.
After 10 years in an unsatisfying job she overcame her inertia and went back to school.

Recent Examples of inertia from the Web

As Noah embarks on a quest to figure out exactly what has happened to him, Arnold starts to delve into deep questions about loneliness and inertia, and about what kinds of change are constructive and what kinds are not.

— constance grady, Vox, "This Bowie-inflected YA novel is an elegant and elliptical portrait of teen angst," 14 June 2018
Powers’s characters blame the usual human motivations: greed, ignorance, inertia, primitive instinct.

— nathaniel rich, The Atlantic, "The Novel That Asks, ‘What Went Wrong With Mankind?’," 11 May 2018
This has been a book about the next step in superheroics, and as with any step or leap forward, there are always people who fear the change and who give in to the inertia.

— graeme mcmillan, The Hollywood Reporter, "'Justice League of America' Writer Dissects a Year of Storytelling," 27 Apr. 2018
The data are clear: If graduates start off underemployed, there is incredible inertia that prevents them from getting out of that rut.

— michelle weise, Washington Post, "First jobs matter: Avoiding the underemployment trap," 1 June 2018
Nevertheless, Lloyd Thacker, executive director of the Education Conservancy and an expert on college admissions, said one of the biggest challenges this kind of proposal faces is just institutional inertia.

— rachel cohen, The Atlantic, "An Unusual Idea for Fixing School Segregation," 23 May 2018
Less defensible reasons are mere inertia or, even worse, the belief on the part of a few judges that cumbersome formal language is needed to give jurors a sense of the majesty of the law.

— The Economist, "Too often juries comprise 12 confused men (and women)," 14 Apr. 2018
But the crisis forced local leaders to break out of the inertia that has characterized efforts to get homeless people into shelters and housing.

— michael smolens, sandiegouniontribune.com, "The confluence of homelessness and hepatitis, again," 20 May 2018
By precisely controlling the tension of the cables, Charlotte can simulate the way that gigantic objects in space are weightless but still have pesky mass and inertia.

— eric limer, Popular Mechanics, "Inside the NASA Holodeck That Brings the ISS to Earth," 16 June 2015

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'inertia.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Did You Know?

Inertia is the inherent property of a body that makes it oppose any force that would cause a change in its motion. A body at rest and a body in motion both oppose forces that might cause acceleration. The inertia of a body can be measured by its mass, which governs its resistance to the action of a force, or by its moment of inertia about a specified axis, which measures its resistance to the action of a torque about the same axiss.

Origin and Etymology of inertia

New Latin, from Latin, lack of skill, from inert-, iners

NEW! Time Traveler

First Known Use: 1713

in the meaning defined at sense 1a

See Words from the same year

inertia Synonyms

Other Physics Terms

amplitude, centrifugal, centripetal, convection, gradient, hysteresis, kinetic, lase, quantum

INERTIA Defined for English Language Learners

inertia

noun

Definition of inertia for English Language Learners

: lack of movement or activity especially when movement or activity is wanted or needed
: a feeling of not having the energy or desire that is needed to move, change, etc.
physics : a property of matter by which something that is not moving remains still and something that is moving goes at the same speed and in the same direction until another thing or force affects it