Morro is a colloquial term in Mexican Spanish, often used to mean 'kid' or 'young guy'. It's a casual and somewhat endearing way to refer to a young person.
In this song, the artist uses morro to describe himself, emphasizing his youth and humble beginnings despite his current success. He sings, "Soy el morrillo de ayer... estoy solo morro con 20 años," highlighting his journey from being a young kid to achieving his dreams.
Get ready to meet Aldo Trujillo, a young artist who's making waves! In "Tan Solo Morro," featuring Polo González, Aldo tells us he's a "morrillo" [kid] who came from humble beginnings and changed his life. He's only 20, but he's already living the good life, with "bolsitas verdes y ladrillos blancos" [little green bags and white bricks] – a hint at some serious business. He's got his feet on the ground, though, and says his "cartera" [wallet] doesn't speak for him.
Aldo's enjoying his new life, with "ropas caras y comidas finas" [expensive clothes and fine foods], but he hasn't forgotten where he came from. He's got a "40 con cargador largo" [a .40 with a long magazine] by his side, so he's clearly not afraid to protect what's his. He's living life to the fullest, because, as he says, "el tiempo lo tenemos prestado" [time is borrowed]. It's a blunt and honest look at a young man's journey from the bottom to the top.