* A misspelling: Perhaps it's meant to be "Lassie," the famous Collie dog from the movies and TV show.
* A nickname: It could be a shortened version of a name like "Leslie" or "Lissa."
* A slang term: It might be a word used in a specific community or region that isn't widely known.
Could you provide more context about where you encountered the word "lsssie"? This would help me understand its meaning.