That's a really good question. Even with the CAPS!!!
OK, so I will attempt to answer the question for you.
Your definition is one of the main definitions for ***. A child with no father. The implication though is that by calling someone a '***' rather than an 'only child' you want to infer the illegitimate aspect of the child. In short, you want to imply that the mother is a ***.
Other uses of '***' imply mixed heritage, mixed breeding in a degenerate manner, a person of low worth or questionable character.
You can have lucky *** in FFXIV who play the game all day long without having to work...but others would refer to them as sad ***. And then those *** NMs like Ifrit which are really difficult to handle without sentinel. And of course, once you do defeat him, the *** drops junk.
Even in these cases though, the use of *** is in a negative sense. In the case of lucky *** it would indicate envy and in the case of Ifrit, frustration with a possible tinge of anger.
Interestingly it is how these words like fvcking-A have become so common place in the language of certain societies that it seems some people have become insensitive to their negative connotations.
Thanks for asking the question. It was a good one.