- 1(usually disapproving) lack of energy; lack of desire or ability to move or change I can't seem to get rid of this feeling of inertia. the forces of institutional inertia in the school system
- 2(physics) a property (= characteristic) of matter (= a substance) by which it stays still or, if moving, continues moving in a straight line unless it is acted on by a force outside itself
Check pronunciation: inertia