Aferres comes from the verb aferrarse, which means "to cling to" or "to hold on to something tightly". It's a powerful reflexive verb that implies a desperate, emotional attachment.
In the song, the singer pleads, "No te aferres, ya no te aferres a un imposible" (Don't cling, don't cling to an impossibility anymore). He uses this word to ask his former lover to stop holding on to a past that can't be revived, perfectly capturing the pain and struggle of letting go.
Talk about brutal honesty. Argentine reggae singer Dread Mar I delivers one of the most unapologetically direct breakup talks you will ever hear in this live track. An ex has suddenly returned, wanting him back, but he shuts the door right in her face. His excuse? It is totally out of his control: "Pero es que no está en mis manos, me he enamorado" ("It is just not in my hands, I fell in love"). He looks her in the eye and tells her that his new partner asked if he still loved his ex, and he flatly said no. Then comes the ultimate salt in the wound—he offers to be buddies and help her move on ("Pero si tú quieres seremos amigos, yo te ayudo a olvidar el pasado" ["But if you want, we can be friends, I will help you forget the past"]). It is delightfully cold, but he insists he is just speaking the truth.
The real sting comes when he reminds her why she is in this mess to begin with. She abandoned him without a word ("Tú te fuiste sin decirme nada" ["You left without telling me anything"]), and while he wept his eyes out back then, he eventually forced himself to move on. Now that she is back expecting a warm welcome, he has met someone new whom he calls "un ser divino" ("a divine being") who taught him to forgive. He begs her not to cling to false hope: "No te aferres, ya no te aferres a un imposible" ("Do not cling, do not cling anymore to an impossible thing"). The verb aferrarse literally means to grasp or hold on tight—like clinging to a ledge—and he makes it clear that holding on to this old flame will only bring pain for both of them.