What does it mean to dislocate a joint?

Definition. Joints have different degrees on stability. Some joints are naturally more stable than others. All joints require soft tissue restraints in the form of ligaments and muscles to increase their stability. When these structures are stretched or torn the joint can become unstable and pop out of place and is then termed a joint dislocation.
No alignment of bone. It means that the two bones that form the joint are no longer in alignment with each other making the joint non functional.