Impersonal verb
In linguistics, an impersonal verb is one that has no determinate subject. For example, in the sentence "It rains", rain is an impersonal verb and the pronoun it corresponds to an exophoric referrent. In many languages the verb takes a third person singular inflection and often appears with an expletive subject. In the active voice, impersonal verbs can be used to express operation of nature, mental distress, and acts with no reference to the doer. Impersonal verbs are also called weather verbs because they frequently appear in the context of weather description.