An accusative verb is a verb which does not take an object and has a subject which is not an agent. The subject has the semantic role of a patient. This distinguishes the accusative verb from an unergative verb, a verb which does not take an object but has a subject which is an agent.
The verb "die" is an unaccusative verb. In the sentence "He died," the subject is a patient. The subject is not actively responsible for the action of the verb. However, in the sentence, "He resigned," the verb "resign" is an unergative verb. The subject is an agent because it is actively responsible for the action of the verb.
The following sentences all have unaccusative verbs:
She has fallen.
They have arrived.
The ice melted.
The window broke.
The guests have left.
Unaccusative past participles can be used as modifiers of a noun but unergative past participles cannot. Compare the following:
the melted snow, the fallen soldiers, the departed visitors
*the shouted employee, *the slept woman, *the telephoned father
An unaccusative verb is a special type of intransitive verb. Unlike an unergative verb, the subject is not an agent but a patient. Another important difference is that unlike unergative past participles, unaccusative past participles can function as nominal modifiers.