In the movie The Godfather, the reason the word ‘mafia’ is not mentioned a single time is because mafia boss Joe Colombo, along with Frank Sinatra, threatened the films production and would only back the filming if they could change the script to their liking.
Mario Puzo, the author of the Godfather books who’d also adapted them to film, had no idea what he was doing as he’d never written a screenplay before. After winning two Oscars, he decided to buy a book on screenwriting to learn how. In the first chapter, it said “Study Godfather I”.
Crooner Al Martino, who played Johnny Fontane in the Godfather, was originally passed over for the movie. He complained to his Mafia “godfather” and eventually got the part, much like his character.
The actor who played Luca Brasi in the Godfather was actually a member of the Colombo crime family sent to monitor the set. Coppola kept the cameras rolling as the actor nervously practiced his lines for the scene, scared that he was going to mess up the big Hollywood movie. He later edited that footage into the film so in-universe the actor’s character was nervously practicing what he was going to say to the intimidating mafioso Don Corleone.
The “real Mafia” did not allow the producers of “The Godfather” to use the word Mafia in the movie. They even sent “family” members to the set to monitor filming. That’s how producers discovered Lenny Montana aka “Luca Brasi”.