What is the opposite of efficient?

The opposite of efficient is inefficient, but there are many other words that describe the opposite depending on context. Common antonyms include wasteful, meaning using more resources than needed, ineffective meaning failing to achieve the desired result, unproductive meaning producing little output for the input, and uneconomical meaning costing too much for the benefit. In everyday language, opposite behaviors include being disorganized, slow, careless, or sloppy, resulting in rework and extra time. In engineering, the opposite of an efficient machine is one that loses most of its energy as waste heat, friction, or noise. For example, an old incandescent light bulb is inefficient because it converts only 10 percent of electricity to light and 90 percent to heat. In work habits, inefficient might mean multitasking poorly, constantly interrupted, or doing tasks in random order. Other opposites include laborious, cumbersome, and extravagant. So while inefficient is the direct linguistic opposite, conceptually the opposite of efficient is any process that requires more time, more money, more energy, or more effort than necessary to achieve the same result, thereby creating waste and frustration.