Inertia
Etymology
From Latin inertia, "idleness, inactivity," from iners, "unskilled, inactive, sluggish," from in-, "not," plus ars, "skill, art." Kepler and then Newton adopted the word for the physical property by which matter resists changes to its motion. Everyday use keeps the flavor of both: a resistance to change that can look like mere laziness.
noun · /ih-NUR-shuh/
The tendency to keep doing what one is already doing — to stay at rest or in motion — and resist change.
What it names
The force of habit and momentum in bodies and organizations alike: the reason things persist on their current course unless something actively redirects them.
Example
The policy survived not because anyone defended it but through sheer inertia — no one wanted the fight of changing it.
Related idea
Momentum is the tendency of motion already underway to continue and build; inertia is the broader resistance to any change of state, including the reluctance to start moving at all.