* Is a misspelling of a different name: There are several names that sound similar, such as "Shanta," "Sasha," or "Natasha."
* Is a made-up name: Some people create unique names for their children, which might not have a defined meaning.
* Has a specific meaning in a particular language or culture: It's possible that "Shantasha" has a meaning in a less commonly known language or cultural context.
If you could provide more context about where you encountered this name, I might be able to help you figure out its meaning.