El idiota de su novio

Here's an interesting way of identifying someone and commenting on them at the same time. The basic formula is el/la + descriptive noun + de + name/relation.

• La loca de Jésica. Jessica, that crazy-ass bitch.
• Mira, ahí viene el naco de Roberto. Look, here comes Roberto, that pinche naco.
• El pendejo de tu hermano. Your asshole (of a) brother.
• La abuelita de Irene. When I heard this, it referred not to the grandmother of Irene but to Irene herself. Irene was in her seventies, not a grandmother herself, and her grandmother was long dead. The meaning: Irene, that decrepit, old bag.
• El idiota de su novio. Her idiot boyfriend.

Let's look more closely at the last example: el idiota de su novio. The idiot does not belong to the boyfriend, nor is he associated with the boyfriend somehow; he is the boyfriend. If we look at this construction as el X de Y, then we are saying that Y is an X. Acaba de llegar el idiota de su novio is a compact way of saying Su novio — que por cierto, es un idiota, como ya sabemos — acaba de llegar. The speaker probably assumes that the listener shares her assessment of the boyfriend, that he is indeed an idiot.

As you can see from these examples, this formula is often used to ascribe negative qualities to someone. However, I once heard the head of a family use this construction in a positive way to introduce his family members on a game show: el bromista de mi cuñado, my jokester (of a) brother-in-law; or my brother-in-law, the joker.

El muy

For emphasis, it is common to insert muy.

• El muy imbécil de Bryan me vio dormida y se metió a la cama. Bryan — what a real jerk he is — saw that I was asleep and snuck into the bed with me. (telenovela dialogue)

El muy muy

By the way, el muy muy refers to someone who think they're better than others. It goes with creerse. ¿Te crees el muy muy? You think you're special, don't? You think you deserve special treatment, don't you?