Did Adam and Eve really know what death was before they disobeyed?

The Orthodox nuance

The question is fair, because Adam and Eve had not yet lived death as we know it. But one can know a danger without experiencing it: a child does not need to burn himself to understand that fire kills. Here the problem is not the lack of a scientific explanation, but the breaking of trust.

In the Orthodox tradition, death is not presented as an arbitrary legal penalty thrown onto man, but as the fruit of separation from God. God is Life. If man cuts himself off from Him, he does not enter a greater freedom, but an existence that becomes corruptible, afraid, and mortal.

So 'in the day that you eat of it you shall die' does not simply mean immediate execution. On that day death begins as corruption, fear, shame, and separation. Physical death will follow as the final fruit of that rupture.