What meaning does ** (double asterisk) have in chinese? I'm reading some web novels, and I noticed that once in a while there's ** double asterisk in the middle of a sentence, but I have no idea what they represent. 

For example: 

 **的挑釁
Just as in the prude American culture, it is a kind of abominable censorship of certain expletives, like 狗日的 (fucking), 他妈的 (fucking), 我肏 (fuck), 我靠 (fuck) etc.