What is the definition of "nullify"?

The definition of "nullify" is to make something invalid or worthless, aligning perfectly with the chosen answer. In legal and general contexts, nullification refers to the act of rendering a document, agreement, or law ineffective. It implies that once something has been nullified, it holds no power or authority. This term is often used in discussions surrounding legislation, contracts, or any agreements that lose their binding force due to various reasons such as a repeal, error, or mutual consent.

In contrasts with the other choices, validating or proving suggests confirming something's legitimacy or truth, rather than negating it. Enhancing the value of something means increasing its worth, which is the opposite of what nullifying implies. Explaining the meaning of something does not correspond with the action of making something invalid. Thus, the focus remains on the core meaning of nullifying as it relates to invalidation, making the selected definition clearly the most accurate.