What is a verb?

A verb is correctly defined as a word that describes an action or a state. This includes words that express physical actions, such as "run" or "jump," as well as mental actions like "think" or "believe," and states of being, such as "is," "are," or "was." Verbs are fundamental to constructing sentences because they indicate what the subject is doing or what condition the subject is in, providing essential information about the relationship between different parts of a sentence.

The other choices do not capture the essence of what a verb is. For instance, while a word that describes a character could be an adjective or another part of speech, it does not relate to the function of a verb. Similarly, a figure of speech represents a rhetorical device or a poetic element, and a brief summary of events pertains to narrative structure rather than the grammatical function that verbs serve. Thus, the definition that identifies a verb as a word that describes an action or state encompasses its broad and critical role in language.