noun
inertia
ihn-UR-shuh
noun
1
In physics, the tendency of an object to keep doing whatever it's already doing — staying still or moving in a straight line — unless a force acts on it.
"Passengers lurch forward when a bus brakes suddenly because of inertia."
"The heavier the object, the more inertia it has to overcome to start moving."
2
A reluctance to act, change, or get started; sluggishness.
"Sheer inertia kept him in the same job for twenty years."
How to Use Inertia
Learner’s notesIn plain EnglishResistance to change — an object resisting a change in motion, or a person resisting getting off the sofa.
Common pairings
overcome inertia
the force of inertia
bureaucratic inertia
Word Forms
inertias plural, inertiae plural, inertiæ plural
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Etymology
From Latin inertia, "lack of skill, inactivity," from iners — in- + ars, "skill." The physics sense was introduced by the astronomer Johannes Kepler.