Every action/reaction causes a displacement in the cosmos.

The motion of the happening of a displacement initiates a series of displacements that total equal in magnitude and opposite in character.

So every action has its own series of reactions to match the displacement of that action with the displacement in an opposite manner.

Some of these reactions may be internal to the object, some may be external.

When there are other forces like friction that are in play, a part of the motion maybe be trapped as passive energy in the object or its associated environment.

In a vacuum,

Actions and reactions come in units of 4 each

Every action will have an internal reaction and an external one. And the external reaction (aka action) will have an associated internal action (aka reaction).

So for 2 objects in a vacuum, a single action is associated with 3 additional forms of energy/displacement.