What is the easy defination of newton 1st law?

F=MA

Newton's first law of motion states that everybody continues in its stateof rest or of uniform motion in a straight line unless compelled by some external impressed agency to change that state. The first part of the law indiates that left to itself a body,if at rest,has a tendency to remain in that state of rest or if moving,it always continues to move in straight line with uniform velocity.This tendency of all matrial bodies to maintain their state of rest or of motion is a fundamental property of matter and is called inetia