Desvestías comes from the verb desvestir, meaning "to undress." While seemingly simple, its use here is quite evocative and intimate.
In the song, Pablo Alborán sings, "Aunque amaba la prisa con la que tu me desvestías" (Although I loved the haste with which you undressed me). This word captures a moment of passionate intimacy and longing, hinting at a past relationship that was intense and physical, making it a memorable and enticing word for learners.
Pablo Alborán opens "Idiota" with a confession over a glass of rum: "No deberia seguir bebiendo esta copa de ron" [I shouldn't keep drinking this glass of rum]. He's not really singing about the drink, he's singing about what it's covering up. Every "I shouldn't" that follows piles onto the same idea: he shouldn't look at old photos from Paris, shouldn't count the days to Valentine's, shouldn't call this late at night. He knows all of it, and does it anyway.
The chorus turns the self-blame into a picture: "Soy carne de cañon para la derrota" [I am cannon fodder for defeat], a man who keeps walking straight into heartbreak and getting flattened by it. It ends on "Soy la copa, rota" [I am the cup, broken], cracked and past fixing. A memory slips in halfway through, how fast she used to undress him, before he drags himself back to the refrain: idiot, cannon fodder, broken cup, over and over, because that's what the week after someone leaves actually sounds like in your head.