To use, consume, spend, or expend thoughtlessly or carelessly. To cause to lose energy, strength, or vigor; exhaust, tire, or enfeeble: Disease wasted his body. To fail to take advantage of or use for profit; lose: waste an opportunity. To destroy completely. Slang To kill; murder. To lose energy, strength, weight, or vigor; become weak or enfeebled: wasting away from an illness. To pass without being put to use: Time is wasting. The act or an instance of wasting or the condition of being wasted: a waste of talent; gone to waste. A place, region, or land that is uninhabited or uncultivated; a desert or wilderness. A devastated or destroyed region, town, or building; a ruin. An unusable or unwanted substance or material, such as a waste product. Something, such as steam, that escapes without being used. Garbage; trash. The undigested residue of food eliminated from the body; excrement. Regarded or discarded as worthless or useless: waste trimmings. Used as a conveyance or container for refuse: a waste bin. Excreted from the body: waste matter. waste (one's) breath To gain or accomplish nothing by speaking.