How Difficult is Climbing Everest?

One measure of climbing difficulty is the rating and climbing has a terminology of it’s own. You read that she just redpointed a 5.12c and wonder if this was something from NASA, or Congress. I have seen Everest described as a simple “walk-up” meaning that no actual climbing is involved so I thought a quick review of what defines climbing might be helpful. I will use the South Col route as the example.