* A misspelling: Perhaps you meant a similar-sounding word like "lithe," which means flexible or graceful.
* A made-up word: It could be a fictional term or a slang expression.
* A technical term: It's possible it's a term used in a specific field, like geology or botany.
To understand what you're looking for, please provide more context. What were you reading or hearing when you encountered the word "lithly"?