vis inertia
Preserved but no longer current.
(Lat., the power of inactivity). It is a common mistake to imagine that inertia means absence of motion; inertia is that property of matter which makes it resist any change. Thus it is hard to set in motion what is still, or to stop what is in motion. Figuratively, it applies to that un- willingness of change which makes men "rather bear the ills they have than fly to others they know not of.
Era: ca. 1898 (Victorian)
Sources & notes
Reproduced from Brewer’s Dictionary of Phrase and Fable (1898 edition, public domain; archive.org, retrieved 2026-07-31; OCR text, minor errors possible). Reflects the scholarship and attitudes of its era.
Common questions
What does “vis inertia” mean?
(Lat., the power of inactivity). It is a common mistake to imagine that inertia means absence of motion; inertia is that property of matter which makes it resist any change. Thus it is hard to set in motion what is still, or to stop what is in motion. Figuratively, it applies to that un- willingness of change which makes men "rather bear the ills they have than fly to others they know not of.
Is “vis inertia” formal or informal?
No register label has been reviewed yet — treat it as neutral and check the usage notes above.