Action and reaction:

Newton’s third law of motion deals with the reaction of a body when a force act on it. Let body A exerts a force on another body B. Body B reacts against this force and exerts a force on body A. The force exerted by body A on B is the action force whereas the force exerted by body B on A is called the reaction force.

Note that action and reaction forces act on different bodies.

Example:

Action and reaction forces act on different objects and in opposite directions. For example, if the rocket pushes the gas out, the gas pushes back against the missile. The forces on different objects (the gas, and the rocket, respectively), and in opposite direction.