1. Useless or profitless activity: Although Karl was accused of spending wastefulness of his time by going down to the river and watching it flow by, he disagreed because he felt it was always a very soothing activity.
2. Using or consuming thoughtlessly or carelessly: The wastefulness of running an air conditioner when no one is home was the subject of a column in the newspaper on energy conservation.
3. The act or practice of expending what is valuable without need or proper use: "Clear cut logging" is considered by some to be an example of wastefulness because no consideration is given to the usefulness of smaller trees, brush, etc. which could also be harvested.