The word is believed to have originated from Havertown, PA, where Bill Hagan, Jordan Frank, Ryan Sweeney, and Jacob Sheetz-Willard first used the term after watching the movie "Teeth."
The word slu originated in a Southern Toronto area. Most recently has been used in correct terminology in a small suburb of Chicago. Elmhurst College, Illinois to be specific.
The word "Slu" has a broad range of uses;
A "slu" can be considered a betrayer, a backstabber, a "dirty" trickster, someone whom is untrustworthy.
For the most part anyone whom is rude.
2. Stop Sluing.
3. (Name) your a slu.
4. Don't be a slu