This adjective describes something that cannot be altered, transferred, or passed to another. Classical Greek used it for unalterable philosophical principles, infallible prophecies, or inviolable agreements. Hebrews 7:24 applies it to Christ's priesthood: because He continues forever, He holds a 'permanent' priesthood—one that cannot pass to a successor. Unlike the Levitical priesthood, which transferred from one mortal priest to another through death, Jesus's priesthood is inviolable and eternal. The term emphasizes both permanence and exclusivity.