Generally, "绅士" (shen shi， gentlemen) refers to the British elegant man with politeness, good manners and high taste, namely gentleman in English.
In the ACG, the word "gentleman" refers to higher abnormal. There are many abnormal people in the world, but not everyone can do abnormal things in the name of a gentleman.
Basically, the abnormal role that can be called gentleman has one or two super skills, such as damaging tempered glass, bringing the dead back to life, twisting feet, using mouth to attack others' spirit, streaking, imagining beyond limits...
Later it was extended that the three-dimensional figure calling himself gentleman is only the abnormality of the two-dimension. In the three-dimension, there are no obvious abnormal behaviors but abnormal words and thought. In a word, they are abnormal on words at most, but on behaviors, they are gentlemen.