Seriously? I have to find a scripture that defines death as death? No, I don't think so. The straight forward reading of the passages is death.

To quote Edward Fudge, "what does death mean? Death. What does death mean? Death. What does death mean? Death."

The wages of sin is death. the gift of God is eternal life. What does death mean? Death.

Then death and Hades were thrown into the lake of fire. The lake of fire is the second death. What does death mean? Death.

For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. What does perish mean? Perish.

The onus is on you to find scripture that defined death as something other than death. Think it through, man.