Final answer:
Toggling a boolean variable named onoffswitch changes its value from true to false or from false to true, usually with a NOT operator in programming.
Step-by-step explanation:
The question is asking to define the operation that toggles the value of a boolean variable named onoffswitch. To toggle a boolean means to change its value from true to false, or from false to true. In most programming languages, this is typically done by using the NOT operator. For example, in languages like C, C++, Java, Python, the toggle operation can be performed with a statement like onoffswitch = !onoffswitch; meaning if onoffswitch is currently true, it will become false, and if it is false, it will become true.