Adicto means "addict". This word is a powerful cognate, meaning it looks and sounds similar to its English equivalent, making it easy to remember.
In the song, Prince Royce isn't singing about a typical addiction. He uses adicto to describe his uncontrollable obsession with a woman, singing "Lo reconozco, soy un adicto" (I recognize it, I'm an addict). This dramatic metaphor perfectly captures the feeling of being hopelessly captivated by someone.
In "Adicto", Prince Royce teams up with Marc Anthony to stage a classic bachata intervention between two buddies. Royce plays the guy who is completely hooked on nightlife, club dancers, and falling head-over-heels every single evening. One day he falls for a blonde who speaks English and French ("Ayer me enamoré de la rubia..."), and the next he is rashly promising to fly a Russian girl out to a shopping mall in Paris. He spends "twenty-five hours" and ten dances a day locked away in dark rooms ("aquel cuartico"), willingly going broke for attention while confessing point-blank: "Lo reconozco, soy un adicto" [I admit it, I'm an addict].
Enter Marc Anthony, who acts as the exasperated voice of reason trying to snap his friend out of it. Marc watches him blow his final pennies on three women at once and warns him that he has sold almost everything he owns. He drops one of the sharpest Spanish idioms in the track: "no tienes dedo pa' tanto anillo" [you don't have enough fingers for so many rings], which mocks Royce for wanting to commit to every girl he sees when he cannot possibly handle them all. Royce simply shrugs with "es que me encantan" [it's just that I love them all], leaving Marc to sigh, relate to the mess, and reassure him that he will survive it.