OK, lemme try it another way.
Christian Baptism places us in a state of Grace. It “enlivens” our soul (meaning it gives it divine life - if we die in such a state, we are assured salvation).
But, while on earth, our spiritual life is mortal, just as our physical lives are mortal. There are things that can kill our bodies, and there are things that can kill our soul.
Injuries which can be assured of killing our bodies are called “mortal” injuries. Such as a gunshot to the heart, or decapitation of the head. Such injuries will ALWAYS cause death, so they are deemed “mortal” injuries (after the Latin word “mortis,” which means “leads to death.”)
We are born with live bodies, but dead souls. Christian Baptism gives life to our souls. But we ourselves can kill that life through mortal sin (unlike our bodies, nobody else can “kill” our soul - we alone “enjoy” that prerogative). This is what we mean by the “death of the soul.”
Fortunately, the Church has a “crash cart” for the soul. Unlike a “crash cart” used by medical professionals to revive a body, the Church’s “crash cart” ALWAYS works. The “crash cart” of the Church is called Confession/Absolution.