рэдкі выпадак

It seems there is a misunderstanding. The term "рэдкі выпадак" is not Spanish; it is actually Belarusian, and it translates to "rare case" in English. Therefore, it does not have a definition in Spanish. However, if you are looking for the Spanish equivalent of "rare case," it would be "caso raro." I can provide definitions for "caso raro" in Spanish if that is what you need. Please let me know how you would like to proceed! tuntematon