Tusa is a popular slang term used in many parts of Latin America to describe the intense feeling of heartbreak, sadness, and bitterness after a relationship ends.
In the song, TINI sings, "Pero esta tusa es tan grande" (But this heartbreak is so big), expressing an overwhelming pain that is going from bad to worse. It's a fantastic and very current word to know if you love modern Latin pop music, as it perfectly captures a common theme in today's hits.
Ever been in a relationship that fell apart so fast you blame bad cosmic aim? In "Cupido", Argentine pop singer TINI puts all the blame on the god of love himself, bluntly singing, "Cupido tiró la flecha y la cagó" (Cupid shot his arrow and screwed up). She is dealing with an ex who constantly demands things without giving anything back ("Tú pides y pides y no das nada"), and while she takes her time replying to texts, she jokes that he takes way too long to actually grow up ("Tardo pa' contestarte / Y tú tardas pa' madurar").
Even with all the frustration, getting over him is rough. TINI sings that no amount of alcohol can erase the pain ("No hay botella que aguante / A borrar este dolor"), calling the massive heartbreak a "tusa" (slang for a painful post-breakup depression). She even brings up the old romantic saying "un clavo siempre saca otro clavo" (one nail drives out another, meaning a new lover cures an old heartbreak), but admits this heavy ache is way too hard to shake off when night falls.