The Creator of Death, The Slayer, The Life-Taker
The One who created the inanimate world, to which all living forms return.
The One who ordains what shall become lifeless.
The One who creates the appearance of death, physically or spiritually.
From the root m-w-t which has the following classical Arabic connotations:
to die, pass away, burn out, be lifeless
to be quiet, still, calm
to be inanimate
to be deprived of sensation
to be spiritually dead, lacking spiritual life
The name Mumīt is not specifically used as a Beautiful Name in the Qur'ān.
The names Mumīt (the life-taker) and Muhyī (the life-giver) are opposites.