Fugaz translates to "fleeting" or "brief." It's a poetic and evocative word that describes something that passes quickly, like a fleeting moment or a shooting star.
In the song, the lyrics state, "Fuimos un polvo fugaz," which literally means "We were a fleeting dust." However, in this context, "polvo" is slang for a sexual encounter. So, the phrase implies that their relationship or encounter was intense but very brief and transient, emphasizing the temporary nature of their connection.
A one-night stand that will not leave the room. Carín León opens like he is filing a police report: "¿Cómo? Sin piedad ni pistola" (How? Without mercy or a gun), then "Me robaste la vida en veinticuatro horas" (You stole my life in twenty-four hours). One day did it, and the crime scene is the furniture. He still has to sleep "En la misma puta cama que te conocí" (In the same damn bed where I met you), and the small things keep ambushing him: "No sé cómo le haré, si aún huele a ti" (I don't know how I'll manage, it still smells like you), "Si aún tengo el brasier que dejaste aquí" (If I still have the bra you left here). He turns the light off. That makes it worse.
The line that actually hurts is a question: "¿Por qué me contaste tus sueños / Si no me veías en ellos?" (Why did you tell me your dreams if you didn't see me in them?). Being let into a future he was never part of is the part he cannot forgive. A full regional Mexican band swells behind him, which makes one night sound like a funeral, and he is fine with the exaggeration: "Fue una noche, la más triste, la más feliz" (It was one night, the saddest, the happiest).