1. Tending to squander money or resources: Leaving one's computer running overnight or when a person is not at home is an example of wasteful use of electricity.
2. Relating to the destruction of a country, people, things, etc.; therefore, causing devastation: The wasteful damage caused by the typhoon required considerable recovery aid in the form of financial support and building supplies.
3. Descriptive of inefficient use of time, effort, and materials: Tzen's wasteful attitude about attending school or completing assignments was frustrating to his teachers and his parents who considered him to be a very bright student.