Inertia is the resistance an object has to a change in its state of motion. Newton's first law of motion states that "An object at rest will always stay at rest and an object in motion will always stay in motion with the same velocity unless acted upon by an unbalanced force." In fact, it is a natural tendency for objects to resist changes in their state of motion. This tendency is called "inertia".
Every object has inertia since everything has mass. And the greater the mass, the greater the inertia will be.