A noun expressing the quality of being beyond death. Paul uses it eschatologically: when the mortal puts on immortality at the resurrection (1 Cor 15:53-54), death is swallowed up in victory. Only God possesses immortality inherently (1 Tim 6:16)—he 'dwells in unapproachable light.' For believers, immortality is the future transformation, not present possession. Classical Greek used it for gods' deathless nature and even for elixirs promising extended life.