Learn Hardcore Italian: Il libro comprato è interessante.

In Italian, when a past participle functions as an adjective—as in Il libro comprato—it typically follows the noun it modifies. This construction is common for forming a concise descriptive phrase that originates from a reduced relative clause.

Does comprato agree in gender and number with libro, and if so, how?

Yes, it does. In Italian, adjectives and participles used adjectivally must agree in gender and number with the noun they describe. Since libro is a masculine singular noun, comprato appears in its masculine singular form.

Why isn’t the relative pronoun and auxiliary verb included, as in Il libro che è stato comprato?

Italian allows the omission of elements like the relative pronoun che and the auxiliary verb in certain contexts when their meaning is clear. In this sentence, Il libro comprato is a shortened form of Il libro che è stato comprato, making the sentence more concise without losing clarity.

Which verb is comprato derived from, and what is its meaning?

Comprato is the past participle of the verb comprare, which means "to buy." Thus, the sentence tells us that the book—having been bought—is interesting.

Is this sentence an example of a passive construction?