Every generation develops its own slang. It often sounds alien to the generations who came before, even as these new words and phrases eventually get adopted into mainstream culture and become just the way people talk. 1950s slang is no different. The decade that birthed rock & roll used old words in whole new combinations, to the consternation of parents and old fogies everywhere, giving us terms like "baby," "cool," and "hipster" that mean more or less the same thing now as they did when they were just rockabilly slang.
Modern American English slang owes a lot to retro slang, so it's worth looking back to see if there's anything else we should be using. Here's a list of 1950s expressions that are worth reviving. Most of them began with either hot-rodder or Beat subcultures, but quickly infiltrated teenage language everywhere.
Cruisin' for a Bruisin'
Are You Writing a Book?
Made in the Shade