Questions & Answers about Lui è nei guai per quel libraccio.
How does the word libraccio give the meaning of "bad book"?
It is made from the noun libro (book). By dropping the final vowel and adding the pejorative (negative) suffix -accio, the word itself becomes "bad book", "nasty book", or "trashy book". This is a very common way in Italian to express a negative opinion about an object without needing to add a separate adjective like brutto or cattivo.
Why is nei guai plural if the English translation says "in trouble"?
The singular noun is il guaio, which means a mess, a problem, or a mistake. However, the Italian idiom for "to be in trouble" almost always uses the plural form: essere nei guai (literally, "to be in the troubles"). The word nei is simply the preposition in combined with the plural definite article i.
Why do we use quel instead of quello here?
The demonstrative adjective quello (that) follows the exact same pattern as the definite articles (il, lo, l'). Because libraccio is a masculine singular noun that starts with a normal consonant, it would take the article il. Therefore, quello changes to match it, shortening to quel. You would only use the full quello before a noun starting with a "lo-trigger" like s+consonant or z (for example, quello zaino).