[Winman]

I agree that spiritual death means separation. When Adam sinned, he did not physically die that very day. But he was separated from God.

Gen 2:17 But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die

Gen 3:8 And they heard the voice of the LORD God walking in the garden in the cool of the day: and Adam and his wife hid themselves from the presence of the LORD God amongst the trees of the garden.

So Adam and Eve's sin separated them from God. Their fig leaves were not good enough to restore fellowship, God had to kill an innocent animal and make skins to restore fellowship or bring them back together again.

And even the story of the prodigal son is a story of separation and reunion.

Luke 15:31 And he said unto him, Son, thou art ever with me, and all that I have is thine. 32 It was meet that we should make merry, and be glad: for this thy brother was dead, and is alive again; and was lost, and is found.

As long as the prodigal son was in sin he was lost and dead. But when he returned he was again with his father and alive.

Rev 22:15 For without are dogs, and sorcerers, and whoremongers, and murderers, and idolaters, and whosoever loveth and maketh a lie.

These are the lost. They are without, they are separated from God.

Compare to the saved:

Rev 22:14 Blessed are they that do his commandments, that they may have right to the tree of life, and may enter in through the gates into the city.