Sargento literally translates to "sergeant," a military rank. However, in this song, it's used in a very specific and intriguing way.
Gabito Ballesteros sings, "No se me raja el sargento," which is a play on words. "Rajarse" means to back out or chicken out. So, "no se me raja el sargento" implies that his "sergeant"—likely referring to his courage, resolve, or even a part of his personality—doesn't back down. It's a clever and unique way to express resilience and toughness.
"Sargento" is Gabito Ballesteros and Calle 24 running through one long boast about money, a rented room, and a woman he can't quite pin down. It opens with "La del proceso no se deja pero yo no la dejo" [The girl I'm pursuing plays hard to get, but I won't give up on her], setting the whole song up as pursuit dressed up as swagger. He stacks the details fast: stacks of cash, a hired room he calls "Que me quiero subir con ella al cuartito de nuez" [That I want to go up with her to the little walnut room], a cooler full of drinks, a woman whose name he never bothered to learn. None of it is meant to add up to anything deeper than the flex itself.
The hook turns his own nickname into a joke he's clearly proud of: "No se me raja el sargento" [My "sergeant" doesn't quit on me], playing on both his reputation and something cruder underneath it. By the time he gets to "Solo sigue la loquera y la detono aquí en mi cama" [The craziness just continues and I unleash it here in my bed], the song has stopped pretending it's about anything but the night itself, ending the same way it started, mid-party, shouting out to "Así nomás, chiquitita" [Just like that, little girl] with nowhere left to go but the next line.