Teso is a popular Colombian slang word that means someone is very skilled, tough, or a "pro" at something. It's the kind of word you learn from locals, not from a textbook.
In the song, Bozá sings, "Dicen que soy bandido y soy muy teso" (They say I'm a bandit and I'm really tough). He uses it to build up his "bad boy" reputation, which he then says he forgets all about when he's with his love. Learning this word gives you a cool piece of authentic slang!
Panamanian artist Boza delivers a smooth reggaeton love track with "Hecha Pa' Mi" (Made for Me), zeroing in on a woman who stands out completely from the crowd. He is obsessed with her independent attitude, describing her as someone who keeps her circle tiny: "No tiene amigas, tiene puras conocidas" (She doesn't have friends, only acquaintances) and avoids drama entirely ("Lo que a ella no le conviene, le da paso y lo esquiva" [Whatever doesn't suit her, she steps aside and dodges]). She lives by her own calm code without stressing, which turns him into her biggest fan while she brings him calm in a chaotic world ("Y en un mundo de guerra / Solo tú me das paz" [And in a world of war, only you give me peace]).
Boza balances this romantic admiration with plenty of playful, blunt swagger. He showers her in luxury, boasting "Te vestí Cartier de arriba abajo" (I dressed you in Cartier from head to toe), referencing the famous French luxury jewelry and watch brand. Even though people label him a streetwise tough guy ("Dicen que soy bandido y soy muy teso" [They say I'm a rascal and I'm very tough/hardcore], using the slang "teso" for someone skilled or intimidating), he completely softens up around her. He compares his total submission to her charm to being locked up without trial ("En tu casa estaré como un preso / Condenado y sin proceso" [In your house I'll be like a prisoner, condemned and without a trial]), fully hooked on someone he believes was tailor-made just for him.