Intransitive verb
In grammar, an intransitive verb does not allow an object. This is distinct from a transitive verb, which takes one or more objects. The verb property is called transitivity.
Examples
In the following sentences, verbs are used without direct object:
"I sneezed."
"My dog ran."
"When he finished the race, he barfed."
"Water evaporates when it's hot."
"You've grown since I last saw you!"
The following sentences contain transitive verbs (they take one or more objects):
"We watched a movie last night."
"She's eating popcorn."
"When I said that, my sister smacked me."
"Santa gave me a present."
Some verbs allow for objects but do not always require one. In other words, a verb may be used as intransitive in one sentence, and as transitive in another:
In general, intransitive verbs often involve weather terms, involuntary processes, states, bodily functions, motion, action processes, cognition, sensation, and emotion.
Valency-changing operations
The valency of a verb is related to transitivity. 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).