<p><strong>noun</strong></p><ul><li>Aeronautics, Rocketry: the action of an aircraft in becoming airborne or of a rocket in rising from its launching site under its own power.</li><li>the instant when such action occurs.</li><li>Informal: the launching or commencement of a project, plan, etc.: The liftoff of the sales campaign will be next month.</li></ul><p><strong>adjective</strong></p><ul><li>able to be shifted or removed by lifting off; capable of being lifted off: I organized the workshop with these liftoff adhesive labels for bins and shelves.</li><li>We used magnetic liftoff nameplates on the lockers.</li></ul>