A verb is a word in the structure of written and spoken languages that generally defines action. In many languages verbs also suggest time: they indicate, to a greater or lesser degree, if an action occurs in the present, the past or the future. They also tell if an action occurred in the past and is still occurring in the present (present perfect tense). Verbs also tell if the subject is performing the action (active voice) or the action is happening to the subject (passive voice).