Pronation is a descriptive term for the normal motion of the foot where there is an inward role of the foot during normal walking and running.

Supination is effectively the reverse and describes the normal outward rolling motion of the foot and ankle during a walking or running.

Overpronation is descriptive term used by some therapists to describe a pronation movement that has carried on further that they would consider to be a normal degree of pronation

or

to describe a relatively normal degree of pronation which lasts longer and exceeds the normal time phase of pronation in the  gait cycle.