A verb expresses action or being.
jump... is... write... become

The verb in a sentence expresses action or being. There is a main verb and sometimes one or more helping verbs. ("She can sing." Sing is the main verb; can is the helping verb.) A verb must agree with its subject in number (both are singular or both are plural). Verbs also take different forms to express tense.

The young girl brought me a very long letter from the teacher, and then she quickly disappeared. Oh my!

If a noun was the first word you ever spoke (Mama or cookie), a verb probably followed just as soon as you learned that "Give cookie" got you better results than "Cookie." In a sentence, the verb expresses what the subject does (She hopes for the job) or what the subject is (She is confident).