Ball of Fire (1941)

A group of academics have spent years shut up in a house working on the definitive encyclopedia. When one of them discovers that his entry on slang is hopelessly outdated, he ventures into the wide world to learn about the evolving language. Here he meets Sugarpuss O'Shea, a nightclub singer, who's on top of all the slang and, it just so happens, needs a place to stay.