* "Straight Up": This is the most common meaning. It's used to emphasize truthfulness or sincerity.
* Example: "STL, this is the best pizza I've ever had!"
* "St. Louis": If you're talking about a place, it likely refers to the city of St. Louis, Missouri.
* Example: "I'm going to a Cardinals game in STL this weekend."
* "Steal": This is a less common use, but it can be used to mean something very good or a good deal.
* Example: "This vintage record player was an STL for $20."
It's important to pay attention to the context to understand the meaning of "STL" in slang.