Subject to death; having a finite lifespan. All living creatures are mortal and will eventually die.
Causing or capable of causing death; fatal. The knight received a mortal wound in battle.
Of or relating to human beings as subject to death. The play explores the mortal condition and the inevitability of death.
He was in mortal fear of losing his job.
Implacably hostile; relentless (especially of rivalry or enmity). The two families were mortal enemies for generations.