means the state of being complete, flawless, and without any defect — or the best possible version of a thing.

from From Latin perfectio, from perficere 'to complete, finish, bring to an end' — built from per- 'thoroughly' plus facere 'to make, do.' So at its root perfection means simply 'thoroughly made,' a thing carried all the way through to its finish. It reached English in the Middle Ages by way of Old French perfeccion.