Unergative

Unergative is a term in linguistics used to describe a subclass of intransitive verbs whose single argument, the subject, denotes an agent that initiates or performs the action. This contrasts with unaccusative verbs, where the subject corresponds to a theme or patient that undergoes a change of state or location rather than an intentional agent. The distinction is commonly discussed in lexical and syntactic theory and has implications for how sentences are structured and how their arguments are licensed.

Examples of unergative verbs include run, laugh, talk, swim, and hurry. In sentences like John runs, The crowd laughed, or She spoke for hours, the subject is an agent performing the action. Examples of unaccusative verbs include rise, fall, arrive, disappear, and die. In sentences such as The sun rose, The door opened, The train arrived, The cat died, the subject corresponds to a change of state or to a location/event rather than an agent.

The unergative/unaccusative distinction matters for syntactic processes such as passivization, object promotion, and argument licensing. In many languages, unaccusatives can form subjects in passive constructions by promoting the internal argument (as in The door was opened), while unergatives do not readily form such agentive passives. Some verbs are ambiguous or cross-linguistically variable in their classification.

Overall, the distinction helps explain patterns of syntax across languages and informs theories about how verbs determine the structure of the verb phrase and its arguments.