Harness is a word that typically refers to a device used for controlling or managing something, such as a horse or a source of energy. There are several synonyms that can be used in place of the word harness, depending on the context. Some common synonyms include control, manage, utilize, exploit, and leverage. In the context of energy sources, the term tap is often used to describe the process of harnessing power. In general, the word harness implies some degree of control or manipulation over a resource or situation, and synonyms for the word reflect different aspects of this basic idea.