What is the state of motion known as?

The state of motion of an object depends on the velocity of the body. If an object's velocity is zero then the object's state of motion represents rest. If an object's velocity is not zero then the state of motion represents motion. 

An object at rest cannot change its state of motion(rest) unless it is moved by an external force. Similarly, an object moving with a constant velocity cannot change its state of motion, unless it is moved by an external force.