Some time ago, I did a study on Jealousy and Envy. I was surprised to learn that modern psychology defines both terms the way that the King James Version does.
"Jealousy" is not that big of a Biblical problem. It means "I have something and you don't, and I'm afraid that you will take it from me." King Saul was jealous that David would take his throne, but the word is usually used to describe God.
"Envy" means "You have something and I don't, and I feel that it should be mine." Envy gets a lot more space in God's Word than jealousy, and it is described as more serious, both to the person being envied, as well as the person doing the envying.
I'll be doing a Bible study on envy over the next few weeks.