Neo pronouns are any pronouns other than the ones I listed. If it's not he/him, she/her, or they/them, then it's a neopronoun. They are for anyone who doesn't feel comfortable with he or she to describe themselves, but also doesn't feel comfortable with being called a they/them.
Pronouns like Xe, ve, and ze are based on the the word “he” but are slightly altered to represent something different. Zir and vir I assume are based on her. When put together it means they are neither a he or a her. That person is instead a Ze/zir.
On occasion you might see the pronoun per which comes from the word person. They are saying “I just want to be seen as a person.”
