Here it is. Online even. Why might you want one? Well if you live here and speak some Spanish, it becomes real clear that you don't understand a large percentage of what the locals are telling you. Why? Slang. These guys have more slang than my Uncle and his buddies in Mississippi.
Aggressive mode: Don't just pull some word off the list and sling it out there. Pick a word and read the examples. Say you want to meet a pretty Mexican girl and say something flirty to her. If you click on "mamacita" this example comes up with the definition: "Oye mamacita, que buena estás."
Defensive approach: Keep a pen and notebook with you. What am I saying? Keep your notes app or your recorder open on your iphone. Record a phrase that you overhear in conversation. Figure out what is actually being said. Easy, no?!
This is actually kind of entertaining because of the online, linked setup, you can click on a word and find out it's meaning. Have fun!!!