What does sisim mean?

"Sisim" is not a recognized word in English or any major language. It's possible you've encountered a misspelling or a word from a specific dialect or slang.

Could you provide more context? For example:

* Where did you see this word? (online, in a book, in conversation)

* What was the surrounding text or conversation?

* What language was it in?

With more information, I might be able to help you figure out what "sisim" means.