could you give some context? in basque there is a word "ziur" which means "sure" or "seguro/a". some words in basque can also be written with "x", but I don't think I have ever seen "xiur" in basque with the meaning of "ziur".
You can't type a few Roman letters and call it a word... If you were able to pronounce it, you could probably find 25 languages with the same word within them. But your four Roman letters don't mean anything. My best guess, if it comes from an authentic source, is that it is Chinese Pinyin without the tone, or incorrectly spelled, in which case it might mean "yes" or "a little".
Thank you all for answering. The word "xiur" is my middle name haha, and well, I really have no idea of what it could mean. But I've being doing some search on google like some of you mentioned and I read that is a "URI language" that based on what it said on the page it was a mathematical language or something like that. And the meaning of "xiur" in that language is "Isis & Osiris". Maybe is in that game that some of you mentioned, I really don't know. I just wanted to have more options, or information ...Hope you find something more. Thanks a lot again