I looked up the word "lust" in an online dictionary and the definition was:

An intense or unrestrained sexual craving. An overwelming desire or craving. Intense eagerness or entusiasm.

I think my definition is an accurate one, actually. Lust is something that is far more intense than a simple feeling. For example, I can like apple pie, or I can even love apple pie, or I can LOVE apple pie. But when my LOVE for apple pie means that I am thinking of nothing else BUT apple pie and would do anything short of killing someone to get it, then that would be lust (for apple pie).

Chris