Filero is Mexican street slang for a knife, usually a switchblade or shiv, tied closely to street culture and danger rather than an ordinary kitchen knife.
In the song, the lyrics describe someone "bien peleonero con fusca y filero" ("a real scrapper with gun and blade"), using filero alongside 'fusca' (gun) to paint a raw, edgy picture of life on dangerous streets.
Get ready to dive into the world of Santa Fe Klan with "FUSCA Y FILERO"! This track is a raw look into the life of someone from the streets, someone who's had to fight for everything. He starts by saying, "Si la muerte me da chance, voy a sacar adelante a mi jefa" [If death gives me a chance, I'm going to get my mom ahead], showing his deep loyalty to his family even while acknowledging the temptations of a dangerous life: "el diablo me aconseja" [the devil advises me].
He's not afraid to stand up for himself and his crew, declaring, "te cobro tu karma y tumbo al que la caga" [I'll make you pay for your karma and take down whoever messes up]. He's a true "callejero" [street person], a "psycho loco pandillero" [crazy psycho gang member] who's always ready for a fight, "bien peleonero con fusca y filero" [very combative with a gun and a knife]. This song is all about loyalty, survival, and staying true to who you are, no matter what. It's a powerful anthem for anyone who's ever had to overcome challenges and prove themselves.