The Greek noun aphanismos comes from the verb aphanizoo (to cause to disappear, to disfigure) and means disappearance, destruction, or corruption — the state of being unseen or ruined. It appears once in the New Testament (Hebrews 8:13), describing the old covenant as "obsolete and aging" and "soon to disappear."
The use of aphanismos in Hebrews 8:13 is part of the epistle's comprehensive argument that the Mosaic covenant was preparatory, not permanent. That which was "aging and obsolete" was drawing toward its aphanismos — its appointed end. This is not failure but fulfillment: the old covenant disappeared because the new and better covenant had arrived in Christ, its high priest, its mediator, and its sacrifice. What appears as loss (aphanismos) is actually completion.