Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.

Xiaosexual does not exist like IT DOES NOT
basicly its a made up sexuality like animesexual etc.

xiaosexual is just a joke made by some xiao (genshin impact) simps. it doesn't make any sense just like my brain when i do math 😃