inertia

noun

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

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 axis.

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 on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Many of these protagonists endure the tedium and humiliation of involuntary psychiatric hospitalizations, losing days and years to paralyzing inertia, and experiencing terrifying delusions of persecution and betrayal. Moira Donegan, New Yorker, 26 Mar. 2025 These aren’t failures of strategy—they’re natural expressions of behavioral inertia. Scott Hutcheson, Forbes.com, 26 Mar. 2025 Why Leaders Resist Flexibility Eikenberry admits that the idea of leadership flexibility faces real hurdles, including complexity, inertia, and cost, to name a few. Dan Pontefract, Forbes, 19 Mar. 2025 Unwritten books also result from the human condition, specifically from its tendency toward inertia: no one ever got around to writing them. Zach Helfand, The New Yorker, 3 Feb. 2025 See All Example Sentences for inertia

Word History

Etymology

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

First Known Use

1713, in the meaning defined at sense 1a

Time Traveler
The first known use of inertia was in 1713

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Cite this Entry

“Inertia.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/inertia. Accessed 2 Apr. 2025.

Kids Definition

inertia

noun
1
: a property of matter by which it remains at rest or in unchanging motion unless acted on by some external force
2
: a tendency not to move or change

Medical Definition

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 (as electricity)
2
: lack of activity or movement
used especially of the uterus in labor when its contractions are weak or irregular

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