Supplizio translates to "torment" or "ordeal". It's a strong, dramatic word that evokes a sense of prolonged suffering, making it quite impactful and less common than everyday words for pain.
In the song, Nitro uses it in the phrase "il mio supplizio della goccia" (my torment of the drop). This refers to the ancient torture method of water torture, where drops of water slowly drive a person to madness. He uses this vivid image to describe his own internal suffering and the slow, agonizing pain of his words and thoughts.
"Too Late" is an apology that arrives after the damage is already done. Nitro keeps telling everyone that everything is okay while he is awake at six in the morning and refusing to look at the sunrise. Time, he says, is the cruelest banker, collecting on a debt he cannot pay.
The verses are unusually blunt about self-hatred. He drinks to stop caring, then likes himself less for having done it. He says he learned to accept himself, but with a blade in his hand. He talks through gritted teeth because opening his mouth would only hurt the person in front of him.
Madame answers from the same place in a different voice. Sadness is her rest and anger is her fuel. She plays the guilty one so she never has to be the wounded one, a fragile plant growing thick thorns so that anyone who steps on it feels it too. Her last line splits the difference: she is the worst deal for anyone who chooses to love her, and the best show for anyone who pays to watch.
The chorus comes back three times and never resolves. Neither of them works out what is missing. They just keep asking.