What is inertia of motion? Give an example.

Inertia is the property of a body which resists a change in its state of rest or of uniform motion.
Mass is the measure of inertia. Heavier objects have more inertia than the lighter objects and greater force will be needed to bring a change in the state of heavier objects than the lighter objects.
For example, stone has more mass than a football, this is the reason a stone resist a change in its inertia than a football does.
Hope, this answer clears you the concept of inertia.