1. Conveying an immoral or sinful reaction: Frank wondered if Sharon thought he had touched or embraced her impurely.

At the dinner party, Sharon was behaving quite impurely because she was making sneering and uncomplimentary remarks to the hostess.

2. Relating to contaminating something by making it unsafe: While Jack was camping with his friends, the food was prepared impurely because of the dust that was blowing into the meat and vegetables which were cooking on the fire.