Noun
a verb (or verb construction) that does not take an object
Source: WordNetIf a language has no cases, but the word order is AVP or PVA, then a classification may reflect whether the subject of an intransitive verb appears on the same side as the agent or the patient of the transitive verb. Source: Internet
In non-valency marking languages such as English, a transitive verb can often drop its object and become intransitive; or an intransitive verb can take an object and become transitive. Source: Internet
Retrograde is also sometimes used as an intransitive verb meaning to become, to appear, to behave or appear to move in a retrograde fashion. Source: Internet
Where the transitivity of a verb only considers the objects, the valency of a verb considers all the arguments the verb takes, including both the subject of the verb and all of the objects (of which there are none for an intransitive verb). Source: Internet
So the syntactic category for an intransitive verb is a complex formula representing the fact that the verb acts as a function word requiring an NP as an input and produces a sentence level structure as an output. Source: Internet