Apathy
Etymology
From Greek “apatheia” (freedom from suffering or passion), from “apathes,” without feeling — “a,” without, plus “pathos,” feeling. For the Stoics apatheia was an admirable serenity, a mind undisturbed by the passions. English inverted the value, so today the word names a deadening indifference rather than a philosophical calm.
noun · /AP-uh-thee/
A lack of interest, motivation, or emotion; profound indifference.
What it names
The flat state of not caring — where things that should move you simply don’t, and you can’t summon the will to act.
Example
Voter apathy, not opposition, was what really doomed the measure — most people simply stayed home.
Related idea
Deliberate detachment is a chosen distance that can be healthy; apathy is an involuntary numbness, a failure of caring rather than a discipline of it.