Why is centrifugal force not real?

Centrifugal force is often called a "fictitious" or "pseudo" force because it only appears to act on objects in a rotating reference frame, not in an inertial frame. In reality, the force is the result of inertia and the object's tendency to move in a straight line, rather than being a force that pushes or pulls the object outwards. The sensation of being pushed outwards in a rotating system is due to the object's inertia resisting the inward force required to keep it moving in a circle.