Menuda literally means "loose change" or "small coins". It's a fantastic example of a common word used in a clever and memorable metaphor.
In the song, Blessd sings "Cambiaste un cheque por la menuda" ("You traded a check for loose change"). He's using this phrase to say his ex left him, someone of high value (a check), for someone new who is worth much less (loose change). It's a powerful and slangy way to talk about a breakup.
Colombian reggaeton star Blessd teams up with hit producer Ovy On The Drums for "Mírame", and it is basically a masterclass in pride meeting heartbreak. Instead of begging his ex to stay, he dares her to look him dead in the eye: "Mírame fijo a la cara si no sientes lo mismo que yo entenderé" [Look me straight in the face if you don't feel the same, I'll understand]. He claims his fast lifestyle was just too much for her ("No cualquiera puede aguantar mi ritmo" [Not just anyone can keep up with my pace]), yet he admits the separation stings. He doesn't even try to hide the pain when he asks, "Mi amor, ¿pa' qué le digo que no?" [My love, why would I tell you no?]. Still, his bruised ego pushes her out the door with a cheeky farewell: "Su adiós duele, pero vuele" [Your goodbye hurts, but fly away].
What makes the track so fun is how petty and honest the breakup details get. He remembers the exact phone call where she dumped him over women on social media that he swears he doesn't even follow ("Peleándome por unos culos que ni sigo" [Fighting with me over girls I don't even follow]). Blessd throws in great Colombian street slang to dismiss her decision, claiming she traded down: "Cambiaste un cheque por la menuda" [You traded a big check for loose change]. In Medellín, menuda refers to pocket change or coins. He shouts out his home turf, Barrio Antioquia, and signs off by telling her to stay "relajadita" [nice and chill]. He is moving on to new flings while hoping somebody else consoles her, perfectly balancing hurt feelings with pure swagger.