A verb is a necessary portion of speech that expresses an action, event, or state of being. Verbs are divided into three types: action verbs (run, leap, write), connecting verbs (is, seem, become), and auxiliary (helping) verbs (can, will, have). They vary in form depending on the tense (past, present, future), voice (active, passive), and mood. Regular verbs follow established conjugation rules, but irregular verbs change suddenly (go → went, eat → ate). Understanding verbs enhances sentence structure and communication by clearly demonstrating what the subject is doing or feeling, resulting in more dynamic and expressive writing.