Unaccusative verb

In linguistics, an unaccusative verb is an intransitive verb whose syntactic external argument is not a semantic agent; that is, it does not actively initiate, or is not actively responsible for, the action of the verb; or it treats the argument like the accusative argument of a transitive verb. Unaccusative verbs thus contrast with unergative verbs. An unaccusative verb's subject is semantically similar to the direct object of a transitive verb, or to the subject of a verb in the passive voice. English unaccusative verbs include die and fall, but not run or resign, which are unergative. They are called unaccusative because, although the subject has the semantic role of a patient, it is not assigned accusative case.