An anticausative verb (abbreviated ) is an intransitive verb that shows an event affecting its subject, while giving no semantic or syntactic indication of the cause of the event. The single argument of the anticausative verb (its subject) is a patient, that is, what undergoes an action. One can assume that there is a cause or an agent of causation, but the syntactic structure of the anticausative makes it unnatural or impossible to refer to it directly. Examples of anticausative verbs are "break", "sink", "move", etc.