Restart slideshow

The Most Popular Slang Word The Year You Were Born

6. 1951: Slippery Slope
The original caption for this photo is: "February 1950: Biker Edith Esposita riding her Matchless machine down a slippery bank during a meeting of an all female motorbike club in Queens, New York."  

Now that's a slippery slope! And that is the slang word added to Merriam-Webster's dictionary in 1951. The term is definitely still in use today, but we don't necessarily mean it in the literal sense. We use it for any action that could lead to an unwanted result.