Caducaste comes from the verb caducar, which means "to expire" or "to become obsolete." It's a striking and somewhat harsh word to use in the context of a relationship.
In this song, Zion uses it to tell a former lover that their relationship, and perhaps even her appeal to him, has "expired." It's a memorable way to express that something is no longer valid or desirable, making it a unique and impactful choice for the lyrics.
Have you ever felt like a past relationship has an expiration date? In "Caducaste," Zion and Chencho Corleone declare that a former flame's time is up. The title itself means "you expired," and the lyrics are a bold statement that the feelings are gone and it's time to move on. The singer tells his ex not to even try convincing him to come back, saying, "Lo que sentía ya caducó" (What I felt has already expired).
Throughout the song, he makes it clear he has moved on to a new life and new women. He even taunts his ex, claiming she still calls him behind her new boyfriend's back. He dismisses her new partner as a "mama's boy" and contrasts his past relationship with his current flings, stating what they had is "periódico de ayer" (yesterday's news). It's a confident, unapologetic anthem about closing one chapter and starting another.