The Most Popular Slang Word The Year You Were Born
19. 1964: Rat Fink
"Rat fink" was added to the dictionary in 1964. It's pretty crazy to think it's actually a legitimate word. The term apparently was originated by Ed Roth. In the 1960s, his cartoons of a mouse called Rat Fink, or RF, were quite popular. It came to mean someone who is a snitch or double-crosser.