Acompleja comes from the verb acomplejar, which means to make someone feel self-conscious or insecure. It's a less common word in everyday conversation, making it stand out.
In the song, the artist sings, "Pensar en eso me acompleja" (Thinking about that makes me feel insecure). He uses this word to express the deep emotional impact of potentially losing his love, highlighting his vulnerability and the intensity of his feelings.
Antes is Gonzy looking at an ex who has visibly moved on. She has healed, changed, and built a new version of herself since they broke up, and he cannot stop noticing it.
The hook is his confession: he wants one more loving look from her, just like the ones she used to give him before. He still remembers the small rituals of their relationship, like how long she took getting ready before a night out, and says there is still so much affection he wants to give her.
The verses shift into his own bravado. He talks up his body and his hustle, jokes that she used to be the quiet one who went to bed early and is now out enjoying herself, and insists that being with him is what changes people.
By the bridge he drops the swagger and admits he genuinely does not know where they stand: whether she is still the same person, whether she waited for him, whether either of them has moved on. He knows the uncertainty could cost him her for good, and that thought weighs on him even as he tries to sound unbothered.