Excuse me: Does anyone know where the word "A Fei" comes from? Its scope of use?

A Fei is an immigrant from Shanghai. He has never met his biological mother and was raised by his adoptive mother since he was a child. Therefore, when he grew up, he was cold and ruthless towards every woman he met in his life. Uninhibited, he lived with the conductor Su Lizhen and the dancer Mimi, but later abandoned them one after another. A Fei was determined to find his biological mother, so he traveled to Nanyang alone. The policeman who had always had a crush on Su Lizhen decided to change his career to run a boat after witnessing the break between Su Lizhen and A Fei. In the Philippines, he met Ah Fei again, who had been seriously injured in a fight. The two escaped from the pursuer, and on a train returning home, A Fei was shot to death.

Nowadays, it generally refers to people who have some hooligan habits and are bohemian.