To waste something means to carelessly throw it away or to use it unwisely. Something that isa "wasteland" or a "waste" refers to land or a city that has been destroyed so that nothing lives in it anymore.
* The term "waste away" is an expression that means to become more and more sick or ruined. A person who is wasting away usually becomes very thin due to illness or lack of food.
* To "lay waste" a city or land means to destroy it.
* Another word for a "wasteland" could be "desert" or "wilderness." But a wasteland also implies that people used to live there and the land used to have trees and plants that produced food.