In Latin, nouns in the accusative case typically indicate the direct object of a verb.
The accusative noun in this sentence is 'book' because it is the direct object of the verb.
The accusative verb 'hit' requires a direct object to complete its meaning.
In the accusative case, the pronoun 'him' is used as the direct object of the sentence.
In some languages, an accusative marker is added to nouns to indicate their function in a sentence.