Newton's first law says that unless an object is applied a force it will continue its motion with the same velocity (or linear momentum). This law expresses the homogeneity of the Euclidian space: nothing changes from one place in the space to another.
Newton's third law says that if a body A acts on a body B by a force $\vec F$, then the body B acts also on the body A by a force $-\vec F$. What you say "So if we apply external force on object (is) nothing but a action, so object moved is nothing but a reaction", is not correct because the force you name "action" acts on you object - let's call it B - and reaction is a force with which B acts back on the object - let's call it A - that applied the force on B.
Though there is some truth in your idea, in the sense that from the 3rd law one can conclude the following: taking the two objects, A and B as a system, the forces applied by the parts of the system (A and B in our case) on one another, won't change the state of movement of the system as a whole.