asleep: describing someone who is in the state of sleep
This is the describing word for a person who is asleep, the still companion of the verb יָשֵׁן, which names the act of sleeping. Almost every time it appears, it simply pictures someone caught in ordinary sleep: Saul lying unconscious in his camp, a mother waking to find her child dead beside her, a lover half-dreaming as her beloved knocks at the door. It can even be used in mockery, as when Elijah taunts that the silent god Baal must be asleep and needs waking.
Because sleep looks so much like death, the word stretches naturally into a gentle picture of the dead. In Daniel 12:2 those who have died are "asleep in the dust of the earth," waiting to be roused. The point is not that death is a nap but that it is not the end: sleepers can be woken. This is one of the clearest Old Testament pictures of resurrection, and the New Testament later leans on the very same image with its own word for the dead who have "fallen asleep."
The two uses share a single idea, the state of being asleep, applied first to living people and then, as a hope-filled figure, to the dead who will wake.